word usage
feels more natural than: "I can''t see any differences between the two" unless it was understood that it is expected that the speaker ought to be able to find a number of specific differences, for
As you say, the differences between "when" and "as" can be subtle, but nevertheless distinct. "When" implies a particular moment in time, and "as" implies concurrent action -- which is to
1 "What is a difference between X and Y?" is also grammatical, but it means something that one hardly ever wants to say: the speaker has deliberately refused to indicate
But even knowing that there are, technically, multiple differences, unless the person asking the question is doing so as a kind of quiz or they are deliberately calling
We use a plural form when we expect that there are (or may be) multiple differences. Are there any differences between these pictures? One has more people, fewer
When you think that there are more than one unlike events involved, use plural. For example: Are there any differences? If you talk about one particular What is the major difference?
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