relative-clausesrelative-pronounssubject-verb-agreement
I wrote a sentence similar to the titular, and got feedback that it should be:
in order to keep consistent plurality (with the plural "Fruits").
But that sounds off to me — I was matching the plurality to singular "mechanism". That is, I was intending to use #1 of the following:
"Fruits are an evolutionary mechanism, which is …"
"Fruits are an evolutionary mechanism, which are …"
What is the correct way of phrasing this sentence, and why?
Well, I found it!
This is from the Blue Book of Grammar and Punctuation.
Sometimes the pronoun who, that, or which is the subject of a verb in the middle of the sentence. The pronouns who, that, and which become singular or plural according to the noun directly in front of them.
So, if that noun is singular, use a singular verb. If it is plural, use a plural verb.
So, in your sentence,
Eatable flowers are a subject that comes up in almost all cooking classes eventually and I am a big fan of them.
A handful of soldiers is/are always better than a mouthful of arguments.
Are is more preferred than is for this sentence.
The actual usages show that it's depend on the meaning.
The graph is from Ngram.
Michael Swan says in his Practical English Usage as follows:
Many singular quantifying expressions can be used with plural nouns and pronouns; plural verbs are normally used in this case.
A number of people have tried to find the treasure, but they have all failed.
(More natural than A number of people has tried ...)(ยง526.2)
Best Answer
As it is, and as others have pointed out, it's difficult to know the correct answer without knowing the rest of the sentence.
If you want to keep the same arrangement, mentally replace "which" with what's being described in the second part of the sentence. What's happening when using "which" is that you're replacing the subject in the second clause, so if you know what's being described, you'll know which tense to use:
Alternatively, what might help is to simplify the sentence so that it's clearer to keep your subject more obvious.
The easiest way to do this is to remove "which"... and you have a couple of options:
If "fruits" is the subject of the sentence, the verb should agree with that. You have a couple of options
Rewrite it as an appositive (note, this will only work if "fruits" is the subject):
[paraphrased from Wikipedia]
Part of the issue is that the two potential subjects are singular and plural... so if you rearrange the sentence, that will change: