Which sentence uses a verb that agrees with its pronoun subject?
a. is i going with you to the grocery store?
b. you children has to wash your hands after playing outside.
c. doesn't you want to know what's inside the box?
d. have i grown any taller since last year?

The answer is D. For A to work it would have to be "Am I going with you to the grocery store? For B to work it would have to be "You children have to wash your hands after playing outside." For C to work it would have to be "Don't you want to know whats inside the box?" Generally the best way to solve these problems is through process of elimination, just so that you're sure that your answer is correct.