In this text words have been removed and only the first few letters are given. Complete the words by filling in the rest of the letters. When you have filled all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. Remember to take great care with spelling as the computer will not recognise a word that is incorrectly spelled. You can use the link to the Cambridge On-line dictionary at the bottom of the page to check any words you are not sure of.
Here the first gap is done for you as an example: The changes described in this report have been driven by large social trends that we have been tracking for many years.