I am having trouble with the following sentence:

"The complexity and diversity of the new platforms is worrying us."

If "complexity" and "diversity" constitute two subjects, then the verb should presumably be "are"; however, the sentence feels more natural with "is". Is this correct? Is there a linguistic term for this occurrence?

The following questions address the general topic of compound subjects, but not specific cases like this:

[Singular] Is/Are [Plural]?
Singular or plural following a list

And the following question seems to have somewhat inconclusive answers:

Verb agreement in “Where is the Messiah and his Kingdom?”

So this question is not really a duplicate of these three.

  • 1
    From the "possible duplicates", the first two are (rather obviously) different from my question, and the answers to the third are somewhat inconclusive. It would be a good thing if questions are judged as being duplicates based on their content, rather than merely their title.
    – Douglas
    Commented Jan 11, 2013 at 12:33
  • The bed and breakfast is on main street.
    – GEdgar
    Commented Apr 29, 2018 at 17:28
  • Possible duplicate of Agreement With Compound Subjects Joined by And
    – Mari-Lou A
    Commented Feb 20, 2019 at 12:19
  • @Mari-LouA: This question is older than the one you linked.
    – Douglas
    Commented Feb 20, 2019 at 17:32

2 Answers 2


Yes, it is just fine. Compare:

  • “My lord and husband is come home.”
  • “Peanut butter and jelly is the best sandwich of all.”
  • “Simon and Garfunkel sounds really mellow right now.”
  • “Tide and time waits for no man.”
  • “Our President and CEO is Joe Schmoe.”
  • “Running and jumping is all I want to do today.”
  • “The master and commander has not yet returned.”
  • “Yesterday is gone; today is fleeting as we speak; tomorrow and tomorrow and tomorrow is all that remains to us.”

It happens when the subject is thought of as one thing. Sometimes it is two things that are so fused as to be thought of together. Sometimes it is two names for the same thing.

Do not let that little and make you think that a plural verb must necessarily follow. It does not have to, and sometimes should not.

  • Thanks, that is a convincing explanation! I had already thought of another example similar to "running and jumping", although I am quite surprised at the "tide and time" case.
    – Douglas
    Commented Jan 10, 2013 at 22:09
  • @Douglas Tide and time are the same thing, not two things. This is the eventful tide, not the soggy one.
    – tchrist
    Commented Jan 10, 2013 at 22:10
  • Yes, I was curious and found your discussion on the matter: english.stackexchange.com/questions/95513/….
    – Douglas
    Commented Jan 10, 2013 at 22:11
  • 1
    Superb examples, and 'It happens when the subject is thought of as one thing. Sometimes it is two things that are so fused as to be thought of together. Sometimes it is two names for the same thing.' is categorical. Commented Sep 7, 2014 at 11:13
  • @tchrist interesting that you instinctively revert to "tide and time are" in your comment...
    – Ant P
    Commented Dec 19, 2014 at 0:16

The number of the verb depends upon whether the worry is caused by the diversity, the complexity, or their combination.

If you could cope with either the complexity of the situation or the diversity alone but in combination they cause worry, then the singular subject requires the verb "is".

On the hand if the complexity alone would cause worry, then there are (at least) two causes that demand a plural verb "are".


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