If I say
Martin and John consider it possible
I would think that "Martin and John" makes the verb "consider" plural, which is the same situation as
The guys consider it possible
or
They consider it possible
But I have heard that if I can take each out of the names out, it becomes singular, so that the correct way to write the first sentence would be
Martin and John considers it possible
because I am able to say "Martin considers it possible" and "John considers it possible".
Which one is correct?
Best Answer
Although there are many questions here which deal with grammatical number and plural subjects, this is the first time I've heard of this "rule". It deserves its own answer.
You are entirely correct. A plural subject requires a plural verb, especially when each "element" of that subject might be considered an individual.
The only time where an apparently plural subject takes a singular verb is when that subject is considered a single entity in its own right:
It's possible that whoever told you that erroneous rule has come across a sentence like that and simply come up with a reason which fits it (fish and chips may both be extracted and the sentence becomes singular).
But it makes no sense: if you remove Martin or John from your sentence, you are only talking about the remaining person. Any verb in that sentence must be singular. To extrapolate that and say that because each element is singular, both together can be is frankly ridiculous. Your intuition that it is ridiculous is correct. If a subject consists of more than identifiable and separable element which are not taken together as a composite entity, it must be plural.