Question

Grammar question ? Mr. Williams is the teacher (who, whom) went to such great trouble to help the students.

Answer 1

i think who

Answer 2

Use who when you are referring to the subject of a clause. Use whom when you are referring to the object of a clause.

John (subject) yelled at Kim (object).
Who yelled at Kim?
John yelled at whom?

In this case Mr. Williams is the subject and the students are the object. So Mr. Williams is the teacher WHO went to great trouble to help the students.

There is a little trick that I learned in high school that helps you figure out which to use. Simply use he or him in place of the word who or whom. If he is correct then you use who. If him is correct use whom.

... HE (not him) went to great trouble ...
likewise
... went to great trouble to help HIM (not he).

Hope that helps.

Answer 3

Yeah, think we covered it.