Why is this sentence incorrect: "Not only this transformation changes the preference of respondents, but it also converts the scale"

and I was asked to write: "Not only does this transformation change the preference of respondents, but it also converts the scale"

Any suggestion will be helpful.

  • Fronting an element like "not only" triggers subject-auxiliary inversion. Since there is no auxiliary present here, one has to be inserted, and this is the "dummy" auxiliary "do". Notice the inverted "does this" (not "this does"). Because "do" is an auxiliary verb, the following 'main' verb must be an infinitival, so "change", not "changes".
    – BillJ
    Jun 30, 2016 at 6:33
  • @BillJ Hmm. Devil's advocate here: how about "Not only Mary left early."? Jul 3, 2016 at 22:43
  • @Araucaria In your example, "not only" is modifying the NP "Mary", but in the OP's example it's modifying a VP. With VPs inversion is triggered when "not only" is fronted, cf. "Ed not only studies three days a week, but he also works part time at McDonalds" vs "Not only does Ed study three days a week, but he also works at McDonalds".
    – BillJ
    Jul 4, 2016 at 11:26
  • @BillJ It can be any type of adjunct so long as it isn't modifying the Subject or part of the Subject, methinks. Jul 4, 2016 at 11:49
  • @Araucaria You've lost me. I thought you were making a point about inversion?
    – BillJ
    Jul 4, 2016 at 12:36

1 Answer 1


This is called do-support and is required when you have a negative such as never before the subject.

Other examples from Wikipedia:

Never did he run that fast again. (wrong: *Never he did run that fast again. *Never ran he that fast again.) Only here do I feel at home. (wrong: *Only here feel I at home.)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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