In the following sentence, should it be 'discuss' or 'discusses'?

This book includes three chapters, which discusses on the examples of adaptation, evolution and survival, providing a further understanding of the three processes.

  • 2
    I discuss, you discuss, he/she/it discusses. And three chapters discuss the examples, never discuss on – Kevin Aug 27 '17 at 20:31
  • @Kevin I'd consider 'discuss on' old-fashioned rather than never acceptable. – Edwin Ashworth Aug 27 '17 at 21:39
  • What would you guess? Can you explain why you are unsure? – herisson Aug 27 '17 at 21:44
  • @EdwinAshworth I've never heard it used (except possibly some VERY specific grammatical constructions), and ngrams shows discuss on wasn't used before about 1738, and has always been about 1,000 times less used than just plain discuss. Certainly, if you have to ask or refer to this question you shouldn't be using it. – Kevin Aug 27 '17 at 21:49

The verb discuss must agree with three chapters, so it needs the plural form, discuss. If the book contains exactly three chapters:

This book includes three chapters, which discuss the examples...
The three chapters in this book discuss...

If it contains more than three chapters, remove the comma:

This book includes three chapters which discuss the examples...
This book includes three chapters that discuss the examples...
Three chapters in this book discuss...

Note, also, that we discuss something, or we have a discussion on something, but we don't discuss on something.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.