It is thought that …
It is believed that …
It has been reported that …
It is a widely held view that …
It has commonly been assumed that …
It may be
It is likely
It could be
It is possible
It is probable
It is almost certain
A likely explanation
A probable explanation
A possible explanation
This inconsistency may be due to …
This discrepancy could be attributed to …
A possible explanation for this might be that …
This rather contradictory result may be due to …
It seems possible that these results are due to …
The observed increase in X could be attributed to …
The possible interference of X cannot be ruled out …
There are several possible explanations for this result.
There are two likely causes for the differences between …
A possible explanation for these results may be the lack of adequate …
Since this difference has not been found elsewhere it is probably not due to …
These findings cannot be extrapolated to all patients.
These data must be interpreted with caution because …
These results therefore need to be interpreted with caution.
These results do not rule out the influence of other factors in …
This account must be approached with some caution because …
It is important to bear in mind the possible bias in these responses.
Although exclusion of X did not …, these results should be interpreted with caution.
However, with a small sample size, caution must be applied, as the findings might not be …
The findings of this study suggest that …
One possible implication of this is that …
Taken together, these results suggest that …
The evidence from this study suggests that …
Initial observations suggest that there may be a link between …
The data reported here appear to support the assumption that …
The findings from these studies suggest that X can have an effect on …
Strategies to enhance X might involve …
Other types of response could include: a), b). …
These results would seem to suggest that the …
There would therefore seem to be a definite need for …
A reasonable approach to tackle this issue could be to …
Another possible area of future research would be to investigate why …
It is likely
It is possible
It is almost certain
There is a possibility
There is a small chance
There is a strong possibility
In general, this requires …
In general terms, this means …
Xs use generally accepted principles to …
X is generally assumed to play a role in …
Authors generally place an emphasis on …
Generally accepted methods for X include: …
Studies which show no effect are not generally published.
Research articles generally consist of the following components:
Quantitative research is generally associated with the positivist paradigm.
Previous studies of X have not dealt with …
Researchers have not treated X in much detail.
Such expositions are unsatisfactory because they …
Most studies in the field of X have only focused on …
Such approaches, however, have failed to address …
Previous published studies are limited to local surveys.
Half of the studies evaluated failed to specify whether …
The research to date has tended to focus on X rather than Y.
Previously published studies on the effect of X are not consistent.
Smith’s analysis does not take account of …, nor does she examine …
The existing accounts fail to resolve the contradiction between X and Y.
Most studies of X have only been carried out in a small number of areas.
However, much of the research up to now has been descriptive in nature …
The generalisability of much published research on this issue is problematic.
Research on the subject has been mostly restricted to limited comparisons of …
However, few writers have been able to draw on any systematic research into …
Short-term studies such as these do not necessarily show subtle changes over time …
Although extensive research has been carried out on X, no single study exists which …
However, these results were based upon data from over 30 years ago and it is unclear if …
The experimental data are rather controversial, and there is no general agreement about …
Smith fails to fully define what …
Jones fails to acknowledge the significance of …
the author overlooks the fact that X contributes to Y.
what Smith fails to do is to draw a distinction between …
the paper would appear to be over-ambitious in its claims.
another weakness is that we are given no explanation of how …
no attempt was made to quantify the association between X and Y.
the main weakness of the study is the failure to address how …
the study fails to consider the differing categories of damage that …
the research does not take into account pre-existing … such as …
the author offers no explanation for the distinction between X and Y.
Smith makes no attempt to differentiate between different types of X.
The study would have been more interesting if it had included …
These studies would have been more useful if they had focused on …
The study would have been more relevant if the researchers had asked …
The questionnaire would have been more useful if it had asked participants about …
The research would have been more relevant if a wider range of X had been explored
A more comprehensive study would include all the groups of …
A better study would examine a large, randomly selected sample of societies with …
A much more systematic approach would identify how X interacts with other variables that are believed to be linked to …
The main weakness with this theory is that …
The key problem with this explanation is that …
However, this theory does not fully explain why …
One criticism of much of the literature on X is that …
However, there is an inconsistency with this argument.
A serious weakness with this argument, however, is that …
One question that needs to be asked, however, is whether …
Smith’s argument relies too heavily on qualitative analysis of …
Smith’s interpretation overlooks much of the historical research …
Many writers have challenged Smith’s claim on the grounds that …
Smith’s analysis does not take account of X, nor does he examine …
It seems that Jones’ understanding of the X framework is questionable.
The existing accounts fail to resolve the contradiction between X and Y.
One of the limitations with this explanation is that it does not explain why…
One major drawback of this approach is that …
Selection bias is another potential concern because …
Perhaps the most serious disadvantage of this method is that …
The main limitation of biosynthetic incorporation, however, is …
Non-government agencies are also very critical of the new policies.
All the studies reviewed so far, however, suffer from the fact that …
Critics of laboratory-based experiments contend that such studies …
Another problem with this approach is that it fails to take X into account.
Difficulties arise, however, when an attempt is made to implement the policy.
Critics have also argued that not only do surveys provide an inaccurate measure of X, but the …
Nevertheless, the strategy has not escaped criticism from governments, agencies and academics.
this method of analysis has a number of limitations.
this method does involve potential measurement error.
there are limits to how far the idea of/concept of X can be taken.
approaches of this kind carry with them various well known limitations.
one of the problems with the instrument the researchers used to measure X was …
Critics question the ability of poststructuralist theory to provide …
Non-government agencies are also very critical of the new policies.
Smith’s meta-analysis has been subjected to considerable criticism.
The most important of these criticisms is that Smith failed to note that …
The X theory has been vigorously challenged in recent years by a number of writers.
These claims have been strongly contested in recent years by a number of writers.
More recent arguments against X have been summarised by Smith and Jones (1982):
Critics have also argued that not only do surveys provide an inaccurate measure of X, but the …
Many analysts now argue that the strategy of X has not been successful. Jones (2003), for example, argues that …
Jones (2003) has also questioned why …
However, Jones (2003) points out that …
The author challenges the widely held view that …
Smith (1999) takes issue with the contention that …
The idea that … was first challenged by Smith (1992).
Smith is critical of the tendency to compartmentalise X.
However, Smith (1967) questioned this hypothesis and …
Smith (1980) broke with tradition by raising the question of …
Jones (2003) has challenged some of Smith’s conclusions, arguing that …
Another major criticism of Smith’s study, made by Jones (2003), is that …
Jones (2003) is critical of the conclusions that Smith draws from his findings.
An alternative interpretation of the origins of X can be found in Smith (1976).
Jones (2003) is probably the best known critic of the X theory. He argues that …
In her discussion of X, Smith further criticises the ways in which some authors …
Smith’s decision to reject the classical explanation of X merits some discussion …
The latter point has been devastatingly critiqued by Jones (2003), who argues that …
In a recent article in Academic Journal, Smith (2014) questions the extent to which …
A recently published article by Smith et al. (2011) casts doubt on Jones’ assumption that …
Other authors (see Harbison, 2003; Kaplan, 2004) question the usefulness of such an approach.
X can be classified into Xi and Xii.
X can be categorised into Xi, Xii and Xiii.
Several taxonomies for X have been developed …
Different methods have been proposed to classify …
X may be divided into several groups: a) …, b) … or c) …
Generally, X provides two types of information: Xi and Xii.
It has become commonplace to distinguish ‘Xi’ from ‘Xii’ forms of X.
X is generally classified into two types: Xi, also known as …, and Xii or …
There are two basic approaches currently being adopted in research into X. One is …
The theory distinguishes two different types of X, i.e. social X and semantic X (Smith, 2013).
The works of Smith fall under three headings: (1) dialogues and …, (2) collections of facts, and …
Smith (2015) draws a distinction between …
Smith (2006) categorised X as being a) …, b) …, or c) …
Smith’s (1980) typology of X is the one most widely–used.
Jones (1987) distinguishes between systems that are a) …, b) …, or c) …
A third method, proposed by Smith et al. (2010), bases the classification on a …
To better understand X, Smith et al. (2011) classified Y into three distinct types using …
For Smith, X is of four kinds: (1) X which …; (2) X which …; (3) X which …; and (4) X which…
In Jones’s system, individuals were classified as belonging to upper or lower categories of …
Smith’s Taxonomy is a classification system used to define and distinguish different levels of …
Smith and Jones (2003) argue that there are two broad categories of Y, which are: a) …, and b) …
includes …
allows for …
helps distinguish …
is useful because …
is very simple and …
provides a basis for …
can vary depending on …
was agreed upon after …
has been broadened to include …
was developed for the purpose of …
is more scientific since it is based on …
is now out of date.
can be problematic.
is in need of revision.
poses a problem for …
has limited utility with respect to …
This topic can best be treated under three headings: X, Y and Z.
The key aspects of management can be listed as follows: X, Y and Z.
There are three reasons why the English language has become so dominant. These are:
There are two types of effect which result when a patient undergoes X. These are …
The disadvantages of the new approach can be discussed under three headings, which are: …
The Three Voices for Mass is divided into six sections. These are: the Kyrie, Gloria, ….
Appetitive stimuli have three separable basic functions. Firstly, they … Secondly, they …
During his tour of Britain, he visited the following industrial centres: Manchester, Leeds, and …
This section has been included for several reasons: it is …; it illustrates …; and it describes…
The Mass for Four Voices consists of five movements, which are: the Kyrie, Gloria, Credo, Sanctus and Agnus Dei.
Smith and Jones (1991) list X, Y and Z as the major causes of infant mortality.
Smith (2003) lists the main features of X as follows: it is X; it is Y; and it has Z.
Smith (2003) argues that there are two broad categories of Y, which are: a) … and b) …
For Aristotle, motion is of four kinds: (1) motion which …; (2) motion which …; (3) motion …
Smith (2003) suggests three conditions for X. Firstly, X should be … Secondly, it needs to be …
X is different from Y in a number of respects.
X differs from Y in a number of important ways.
There are a number of important differences between X and Y.
Areas where significant differences have been found include X and Y.
In contrast to earlier findings, however, no evidence of X was detected.
A descriptive case study differs from an exploratory study in that it uses …
Jones (2013) found dramatic differences in the rate of decline of X between Y and Z.
Women and men differ not only in physical attributes but also in the way in which they …
The nervous systems of Xs are significantly different from those of Ys in several key respects.
Both X and Y share a number of key features.
There are a number of similarities between X and Y.
The effects of X on human health are similar to those of Y.
Both X and Y generally take place in a ‘safe environment’.
These results are similar to those reported by (Smith et al. 1999).
This definition is similar to that found in (Smith, 2001) who writes:
The return rate is similar to that of comparable studies (e.g. Smith et al. 1999).
The approach used in this investigation is similar to that used by other researchers.
Studies have compared Xs in humans and animals and found that they are essentially identical.
In the trial, women made more/fewer errors than men.
Women tend to have greater/less verbal fluency than men.
Women are more/less likely than men to perform well in tests.
Women are more/less accurate in tests of target-directed motor skills.
Women tend to perform better/worse than men on tests of perceptual speed.
Women are faster/slower than men at certain precision manual tasks, such as …
Women are more/less likely to suffer from X when the front part of the brain is damaged.
The part of the brain connecting the two hemispheres may be more/less extensive in women.
The term ‘X’ was first used by …
The term ‘X’ can be traced back to …
Previous studies mostly defined X as …
The term ‘X’ was introduced by Smith in her …
Historically, the term ‘X’ has been used to describe …
It is necessary here to clarify exactly what is meant by …
This shows a need to be explicit about exactly what is meant by the word ‘X’.
The term ‘X’ refers to …
X can broadly be defined as …
X can be loosely described as …
The term ‘X’ encompasses A), B), and C).
X can be defined as … It encompasses …
The term ‘X’ has come to be used to refer to …
The term ‘X’ is generally understood to mean …
In the literature, the term tends to be used to refer to …
In broad terms, X can be defined as any stimulus that is …
Whereas X refers to the operations of …, Y refers to the …
The broad use of the term ‘X’ is sometimes equated with …
The term ‘X’ has been used to refer to situations in which …
The term ‘disease’ refers to a biological event characterised by …
The term ‘X’ is a relatively new name for a Y, commonly referred to as …
Defined as X, obesity is now considered a worldwide epidemic and is associated with …
The definition of X has evolved.
There are multiple definitions of X.
Several definitions of X have been proposed.
In the field of X, various definitions of X are found.
The term ‘X’ embodies a multitude of concepts which …
This term has two overlapping, even slightly confusing meanings.
Widely varying definitions of X have emerged (Smith and Jones, 1999).
Despite its common usage, X is used in different disciplines to mean different things.
Since the definition of X varies among researchers, it is important to clarify how the term is …
has evolved.
has varied over time.
has been extended to refer to …
has been broadened in recent years.
has not been consistent throughout …
has changed somewhat from its original definition …
X is a contested term.
X is a rather nebulous term …
X is challenging to define because …
A precise definition of X has proved elusive.
A generally accepted definition of X is lacking.
Unfortunately, X remains a poorly defined term.
There is no agreed definition on what constitutes …
There is little consensus about what X actually means.
There is a degree of uncertainty around the terminology in …
These terms are often used interchangeably and without precision.
Numerous terms are used to describe X, the most common of which are ….
The definition of X varies in the literature and there is terminological confusion.
Smith (2001) identified four abilities that might be subsumed under the term ‘X’: a) …
‘X’ is a term frequently used in the literature, but to date there is no consensus about …
X is a commonly-used notion in psychology and yet it is a concept difficult to define precisely.
Although differences of opinion still exist, there appears to be some agreement that X refers to …
The term ‘X’ is used here to refer to …
In the present study, X is defined as …
The term ‘X’ will be used solely when referring to …
In this essay, the term ‘X’ will be used in its broadest sense to refer to all …
In this paper, the term that will be used to describe this phenomenon is ‘X’.
In this dissertation, the terms ‘X’ and ‘Y’ are used interchangeably to mean …
Throughout this thesis, the term ‘X’ is used to refer to informal systems as well as …
While a variety of definitions of the term ‘X’ have been suggested, this paper will use the definition first suggested by Smith (1968) who saw it as …
For Smith (2001), X means …
Smith (2001) uses the term ‘X’ to refer to …
Smith (1954) was apparently the first to use the term …
In 1987, psychologist John Smith popularized the term ‘X’ to describe …
According to a definition provided by Smith (2001:23), X is ‘the maximally …
This definition is close to those of Smith (2012) and Jones (2013) who define X as …
Smith, has shown that, as late as 1920, Jones was using the term ‘X’ to refer to particular …
One of the first people to define nursing was Florence Nightingale (1860), who wrote: ‘… …’
Chomsky writes that a grammar is a ‘device of some sort for producing the ….’ (1957, p.11).
Aristotle defines the imagination as ‘the movement which results upon an actual sensation.’
Smith et al. (2002) have provided a new definition of health: ‘health is a state of being with …
X is defined by Smith (2003: 119) as ‘… …’
The term ‘X’ is used by Smith (2001) to refer to …
X is, for Smith (2012), the situation which occurs when …
A further definition of X is given by Smith (1982) who describes …
The term ‘X’ is used by Aristotle in four overlapping senses. First, it is the underlying …
X is the degree to which an assessment process or device measures … (Smith et al., 1986).
includes …
allows for …
highlights the …
helps distinguish …
takes into account …
poses a problem for …
will continue to evolve.
can vary depending on …
was agreed upon after …
has been broadened to include …
intended to …
modelled on …
too simplistic:
useful because …
problematic as …
inadequate since …
in need of revision since …
important for what it excludes.
the most precise produced so far.
steep sharp steady gradual marked fall rise drop decline increase decrease
is the growth of … is the high rate of … is the variability of … is the dominance of … is the rapid decrease in … is the steady decline of … is the general pattern of … is the dramatic decline in … is the continual growth of … is the difference between … is the phenomenal growth of …
Production of X peaked in 1985. X rose to a high point and peaked in … The peak age for committing a crime is 18. The number of Xs reached a peak during … Production of X reached a low point in 1990. The rate fell to a low point of $5.00 at the end of the year.
Over half of those surveyed indicated that …
Nearly half of the respondents (48%) agreed that …Approximately half of those surveyed did not comment on …Less than a third of those who responded (32%) indicated that …
The number of first marriages in the United Kingdom fell by nearly two-fifths.
Of the 148 patients who completed the questionnaire, just over half indicated that …
Singapore has the highest proportion of millionaire households.
The annual birth rate dropped from 44.4 to 38.6 per 1000 per annum.
The proportion of live births outside marriage reached one in ten in 1945.
Scotland had the lowest proportion of lone parents at only 14 per cent.
The proportion of the population attending emergency departments was 65% higher in X than …
70% of those who were interviewed indicated that …
Since 1981, England has experienced an 89% increase in crime.
The response rate was 60% at six months and 56% at 12 months.
In 1960 just over 5% of live births in 1960 were outside marriage.
Returned surveys from 34 radiologists yielded a 34% response rate.
He also noted that fewer than 10% of the articles included in his study cited …
With each year of advancing age, the probability of having X increased by 9.6% (p = 0.006).
The mean income of the bottom 20 percent of U.S. families declined from $10,716 in 1970 to …
X found that of 2,500 abortions, 58% were in young women aged 15-24, of whom 62% were …
The average of 12 observations in the X, Y and Z is 19.2 mgs/m …
This figure can be seen as the average life expectancy at various ages.
The proposed model suggests a steep decline in mean life expectancy …
Roman slaves probably had a lower than average life expectancy.
The mean age of Xs with coronary atherosclerosis was 48.3 ± 6.3 years.
Mean estimated age at death was 38.1 ± 12.0 years (ranging from 10 to 60+ years)
The mean score for X was subjected to multivariate analysis of variance to determine …
The mean income of the bottom 20 percent of U.S. families declined from $10,716 in 1970 to …
Estimates of X range from 200,000 to 700,000 and up to a million or more.
The respondents had practised for an average of 15 years (range 6 to 35 years).
The participants were aged 19 to 25 and were from both rural and urban backgrounds.
Rates of decline ranged from 2.71– 0.08 cms per day with a mean of 0.97 cms per day.
They calculated ranges of journal use from 10.7%–36.4% for the humanities, 25%–57% for …
The evidence shows that life expectancy from birth lies in the range of twenty to thirty years.
At between 575 and 590 metres depth, the sea floor is extremely flat, with an average slope of …
The mean income of the bottom 20 percent of U.S. families declined from $10,716 to $9,833.
may cause
can lead to
can result in
caused by
resulting from
stemming from
can give rise to
X has contributed to the decline in …
It is now understood that X plays an important role in …
A number of factors play a role in determining the effects of …
The mixing of X and Y exerts a powerful effect upon Z through…
Recent research has revealed that X has a detrimental effect on …
A number of factors are known to affect the volume and type of …
All these factors can impact on the efficiency and effectiveness of …
X is only one of many factors that help to determine the quality of
affect X.
shape X.
predict X.
increase X.
influence X.
determine X.
affect the rate of …
be associated with …
increase the risk of …
be partially responsible for …
play a role in determining X .
One reason why Xs have declined is that …
A consequence of vitamin A deficiency is blindness.
The causal role of X in Y has been demonstrated by …
The most likely causes of X are poor diet and lack of exercise.
The causes of X have been the subject of intense debate within …
X can have profound health consequences for older people.
Physical activity is an important factor in maintaining fitness.
Many other medications have an influence on cholesterol levels.
X is a key factor in …
X is a major influence on …
X has a positive effect on …
X has a significant impact on …
X is an important determinant of …
X and Y are important driving factors of Z.
X is generally seen as a factor strongly related to Y.
X is a significant contributory factor to the development of …
This work has revealed several factors that are responsible for …
The study found that loneliness has twice the impact on early death as obesity does.
risk
common
dominant
predictive
important
significant
underlying
contributing
confounding
complicating
owing to
because of
as a result of
as a consequence of
Therefore,
Consequently,
Because of this,
As a result (of this),
thus
break
thereby
X may have been an important factor in …
X may have contributed to the increase in …
X may have played a vital role in bringing about …
X may have been caused by an increase in …
In the literature, X has been associated with Y.
A high consumption of X could be associated with infertility.
X in many cases may be associated with certain bacterial infections.
There is some evidence that X may affect Y.
It is not yet clear whether X is made worse by Y.
This suggests a weak link may exist between X and Y.
The use of X may be linked to behaviour problems in …
The human papilloma virus is linked to most cervical cancer.
The findings indicate that regular exercise could improve cognitive function in people at risk of …
For example, the word ‘doctor’ used to mean a ‘learned man’. For example, Smith and Jones (2004) conducted a series of semi-structured interviews in … Young people begin smoking for a variety of reasons. They may, for example, be influenced by ….
This is exemplified in the work undertaken by … Another example of what is meant by X is … This distinction is further exemplified in studies using … An example of this is the study carried out by Smith (2004) in which … The effectiveness of the X technique has been exemplified in a report by Smith et al. (2010)
This is evident in the case of … This is certainly true in the case of … The evidence of X can be clearly seen in the case of … In a similar case in America, Smith (1992) identified … This can be seen in the case of the two London physics laboratories which …
X is a good illustration of … X illustrates this point clearly. This can be illustrated briefly by … By way of illustration, Smith (2003) shows how the data for … These experiments illustrate that X and Y have distinct functions in …
well-known notable classic useful important example of X is …..
Young people begin smoking for a variety of reasons, such as pressure from peers or … The prices of resources, such as copper, iron ore, and aluminium, have declined over … Pavlov found that if a stimulus, for example the ringing of a bell, preceded the food, the … Many diseases can result at least in part from stress, including: arthritis, asthma, and migraine. Gassendi kept in close contact with many other scholars, such as Kepler, Galileo, Descartes, and …
This case has shown that …
This has been seen in the case of …
The case reported here illustrates the …
Overall, these cases support the view that …
This case study confirms the importance of …
The evidence presented thus far supports the idea that …
This case demonstrates the need for better strategies for …
As this case very clearly demonstrates, it is important that …
This case reveals the need for further investigation in patients with …
This case demonstrates how X used innovative marketing strategies in …
Recent cases reported by Smith et al. (2013) also support the hypothesis that …
In support of X, Y has been shown to induce Y in several cases (Smith et al., 2001).
The section below describes … What follows is an account of … In the following pages, I will present … The following is a brief description of … In the section that follows, it will be argued that … The problem of X is discussed in the following section. A more detailed account of X is given in the following section. The structure and functions of X will be explained in the following section. The following part of this paper moves on to describe in greater detail the…
Regarding X, … As regards X, … In terms of X, … In the case of X … With regard to X, … With respect to X, … On the question of X, … As far as X is concerned, …
As discussed above, … As explained earlier, … As previously stated, … As indicated previously … As described on the previous page, … As was mentioned in the previous chapter, … Returning (briefly) to the (subject/issue) of X, … As explained in the introduction, it is clear that … As was pointed out in the introduction to this paper, …
Turning now to … Let us now turn to … Let us now consider … Moving on now to consider … Turning now to the experimental evidence on … Before proceeding to examine X, it is important to … Before explaining these theories, it is necessary to … Having defined what is meant by X, I will now move on to discuss … So far this paper has focused on X. The following section will discuss … This chapter has demonstrated that … It is now necessary to explain the course of … Having discussed how to construct X, the final section of this paper addresses ways of … This section has analysed the causes of X and has argued that … The next part of this paper will …
Another significant aspect of X is …
In addition, it is important to ask …
Unlike Smith, Jones(2014) has argued …
In contrast to Smith, Jones (2014) maintains …
Despite this, little progress has been made in the …
However, this system also has a number of serious drawbacks.
On the other hand, in spite of these recent findings about the role of …,
Thus far, the thesis has argued that …
The previous section has shown that …
To conclude this section, the literature identifies …
This section has reviewed the three key aspects of …
In summary, it has been shown from this review that …
This chapter has described the methods used in this investigation and it has …
This section has attempted to provide a brief summary of the literature relating to …
This chapter began by describing X and arguing that … It went on to suggest that the …
In this section, it has been explained that … The chapter that follows moves on to consider the…
In the chapter that follows, I present …
The next chapter describes the synthesis and evaluation of …
A summary of the main findings, together with …, is provided in the next chapter.
The next chapter describes the procedures and methods used in this investigation …
In the next section, I will present the principal findings of the current investigation …
These analytical procedures and the results obtained from them are described in the next chapter.
Time phrases associated with the use of the present perfect tense: past and present connected - close To date, little evidence has been found associating X with Y. Up to now, the research has tended to focus on X rather than on Y. So far, three factors have been identified as being potentially important: X, Y, and Z. Since 1965, these four economies have doubled their share of world production and trade.
Until recently, there has been little interest in X. Recently, these questions have been addressed by researchers in many fields. In recent years, researchers have investigated a variety of approaches to X but … More recently, literature has emerged that offers contradictory findings about …
The past decade has seen the rapid development of X in many … Over the past 30 years there has been a significant increase in … Over the past century there has been a dramatic increase in … Over the past few decades, the world has seen the stunning transformation of X, Y and Z.
The present perfect tense may also be used to describe research or scholarly activity that has taken place recently - close Several studies have revealed that … Previous studies of X have not dealt with … A considerable amount of literature has been published on X. There have been several investigations into the causes of illiteracy (Smith, 1985; Jones, 1987). The new material has been shown to enhance cooling properties (Smith, 1985, Jones, 1987). Invasive plants have been identified as major contributing factors for the decline of … The relationship between a diet high in fats and poor health has been widely investigated (Smith, 1985, Jones, …
For reference to single investigations or publications in the past, the simple past tense is used - close
An experimental demonstration of this effect was first carried out by …
The first experimental realisation of …, by Smith et al. [12], used a …
The first systematic study of X was reported by Patel et al. in 1986.
Smith and Jones (1994) were the first to describe X, and reported that …
X as originally isolated from Y in a soil sample from … (Wang et al., 1952).
In 1975, Smith et al. published a paper in which they described …
In the 1950s, Gunnar Myrdal pointed to some of the ways in which …
In 1981, Smith and co-workers demonstrated that X induced in vitro resistance to …
In 1984, Jones et al. made several amino acid esters of X and evaluated them as …
In 1990, Patel et al. demonstrated that replacement of H2O with heavy water led to …
Thirty years later, Smith (1974) reported three cases of Candida Albicans which …