Hello @ziyinini No, you didn’t do anything wrong and the corpus has not been updated (it is not a monitor corpus that grows in size). We didn’t specify whether you need to search for analysis as a word or a lemma. If you put analysis in the word box, you only examine the form analysis (singular). If you put it in the lemma box, you examine both analysis and analyses. That’s why you got a slightly higher frequency (1,346 hits). The same was the case for Task 4. So, there is no right or wrong; it just depends what you want to examine. Perhaps I will add this to the answer key next time, so thank you for your question.