Do/Does Clash

[Guest]

I know do is for plural and does singular but sometimes its confusing.


Could anyone give some Tricky/Good example where Do is used rather than Does.

[esledge]

In general, "does" is singular and "do" is plural, as you say. Examples:

Singular
Felicia does her best.
He does his best.
It doesn't work.

Plural
James and Larry do their best.
The switches don't work.

However, personal pronouns such as I, you, we, and they are exceptions. Even when the antecedent is singular, use "do" as you would with a plural subject:
I do my best.
You don't have the time.
They do the math on paper.

By the way, this exception is not critical for GMAT purposes. The personal pronouns I, you, and we are virtually unused on the GMAT (at least, I can't think of any questions with them). The only personal pronoun commonly used is "they," which would require "do," in agreement with the more general rule that "do" goes with a plural subject.