clever MNers: please help me explain 'who' or 'whom' to ds

[curtaincall]

He just asked me to explain the difference. Started to give him examples but can't explain the syntax. Told him I'd look it up ...

If you'd say "he", use "who". If you'd say "him", use "whom".

He wanted to go to the shop. Who wanted to go to the shop?

I gave the book to him? To whom did you give the book? (Whom did you give the book to?)

In grammar terms, if it's the subject of the sentence, use "who", and if it's the object of the verb, use "whom".

Thanks for that. Hope that answer will do. I found myself using examples too but the definition is useful.