对【duì】

对 points an action at a person. It goes before the verb, with the person attached.

对 against 跟

跟 is a two-way "with" – both people take part. 对 is one-way, aimed at the listener.

对…好 and other attitudes

A large group of expressions say how someone treats or regards something, and they all take 对.

对 as "correct"

A separate use, and the commonest one in conversation. 对 alone confirms what was just said.

对不对 tacked on the end asks for confirmation, the way 是不是 does.