A who，whom

　　在正规英语中我们用介词+whom结构：

　　With whom did you go?

　　你和谁一起去的?

　　To whom were you speaking?

　　你刚才在跟谁说话?

　　但在日常口语中我们常把介词置于句末。这时一般将whom变成who：

　　Who did you go with?

　　Who were you speaking to?

　　B which，what

　　在正规英语中我们用介词+which/what结构：

　　To which address did you send it?

　　你把东西寄到哪个地址去了?

　　On what do you base your theory?

　　你的理论依据是什么?

　　在非正规英语中我们将介词置于句末：

　　Which address did you send it to?

　　What do you base your theory on?