duoskipper.js

// ==UserScript==
// @name           DuoSkipper
// @description    Skip test questions on Duolingo by pressing Enter.
// @include        https://www.duolingo.com/practice
// @version        1.0
// ==/UserScript==

window.addEventListener('load', function() {
  $(document).keypress(function(evt) {
    if (evt.keyCode == 13) {
      $('#skip_button').click();
      setTimeout(function() {
        $('#next_button').click();
      }, 1e3)
    }
  });
}, false);