介词用于句子末尾的几种情况

在下述三种情况下，介词通常要放在句子的尾部。

①在由who，what，which等引导的特殊疑问句中。

Whom did he send the letter to？他把信寄给谁了？
Where did he come from？他从哪里来？
②在不定式短语作定语的句子中。

There is nothing to be afraid of. 没有什么可怕的东西。

He wants to get a pen to write a note with. 他想找一支钢笔写个便条。

Has she found a house to live in？她找到房子住了吗？
③在无关系代词或以that引导的定语从句中。

Water is something we can't do without. 我们不能没有水。

He is a man （that）you must be on guard against. 他这个人你必须提防。

比较
Is it the mistake （that）he accused you of？这就是他指责你犯的错误吗？。