Is the following sentence grammatical?

Secondly, doing research and inventing new things are only possible if someone has understood the concepts in that particular topic or area.

I'm concerned about the use of the verb to be.  Grammarly claims that I should use "is" instead of "are".  I am under the impression that I am listing two activities – doing research and inventing – and hence, I should use "are".  Is it not similar to saying "X and Y are not feasible" or "X and Y are bad boys"?

  • 2
    Grammarly is a computer program that only understands grammar to a very limited extent; while it is useful in that it identifies a lot of grammatical errors, some of its comments are completely wrong and should be ignored. Commented Aug 28, 2020 at 12:20
  • 1
    Grammarly does not understand language at all. The purpose of Grammarly is not to teach language to you. The purpose of Grammarly is to try and teach language to a piece of metal that literally does not even know what the word "language" means, or indeed that it has a meaning at all. Grammarly is not a tool written by humans for humans. It is a tool written for robots by morons. You are not in its target audience.
    – RegDwigнt
    Commented Aug 28, 2020 at 12:31
  • I’m voting to close this question because bug reports for a piece of software are best directed at developers of said piece of software.
    – RegDwigнt
    Commented Aug 28, 2020 at 12:35
  • You were right.
    – Peter
    Commented Aug 28, 2020 at 12:40

1 Answer 1


Both "is" and "are" are correct in your sentence.

If "doing research and inventing new things" is considered as representing a single idea, a singular verb is called for; If these are considered separate ideas, a plural verb is called for.

So it is not a question of right or wrong, strictly speaking.

But because in your case the two are closely related, I would prefer going with the "is" version myself.

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