Open the REPL and import some stuff:
Welcome to Scala 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_131).
Type in expressions for evaluation. Or try :help.
scala> import scala.concurrent._, duration._, ExecutionContext.Implicits.global
import scala.concurrent._
import duration._
import ExecutionContext.Implicits.global