★that不引导介词的宾语从句，至于except that, in that, save that, but that等是复合从属连词。
I know（that）you have met him.
Let's suppose that one day this happens to you.
I told him（that）he was wrong.
在少数动词如：think, believe, suppose, expect, imagine,calculate, fancy, reckon, be supposed , seem, appear, feel as if, look as if, look like等后面的从句中的否定词经常转移到主句谓语动词上,这叫否定前置/否定转移。
(hope“希望”, guess“认为”后的宾语从句否定不前置。i hope not.“我希望不是那样的”，是i hope so.的否定式。i don’t hope so.是对hope的否定：“我不希望如此”。)
如：I don't think it will be very cold today.
I don't think you are right.
I don't believe he has finished his work.
I don’t think diplomacy is a field for private enterprise.我不认为外交是私人可以经营的领域。
We didn’t think we’d be this late.我们没有料到我们会来得这么晚。
Why do you think we can't change your note?
I do believe tom never tells a lie.
They still didn’t believe that the food would come.他们仍然不相信洪水会来临。
I can’t believe that they are married.我不能相信他们已结婚了。
I had thought that he would not come.
⑤当宾语从句中有no, never, hardly, not at all, not a bit, not...enough, can’t help doing等时不能否定转移。
I think i can't help laughing if i see it.
I believe he never tells a lie.
We think it wrong that he told a lie to everyone.
We thought it a pity that she should have missed the chance.
2. whether, if引导宾语从句：表示“是否”可互换，口语中常用if。
He asked if she would come.
Tell me what you want.
Do you know who will come at the meeting?
如:Do you know whom（who）he will invite?
①whose, which, what三个词都带有形容词性质。whose表示所有，意为“谁的”；which意为“哪一个 ”，what意为“什么”。如：
Whose book it is not important.
Please tell me which school you want to go.
He didn't know what time it was.
如：Which food，说话人一般指眼前的或明确范围的几种“food”；what food则指许多“food ”，而且说话人心中没有数。
I don't know which / what food you want.
I don't know when the meeting will be held.
Please tell me where i can find tom.
He explained to me why he was absent from the meeting.
Can you tell me how i can get to the post office?
5.可用whatever, whoever, whomever, whenever, wherever等引导宾语从句。
Please write down whatever he is saying.
I don't know whoever will come.
I'll do whatever you ask me to.
6.表示爱憎情感的动词，如：enjoy, hate, love, like, dislike, don’t mind, resent, appreciate（感激）等以及某些介词结尾的短语动词
如：count on, depend on, rely on, see to, look forward to, be fond of, feel like, see to, 等后，即使没有宾补也要先接形式宾语it，再接宾语从句。
I like it when she smiles at me.
I love it when you sing.
I hate it if i am spoken to loudly in public.
★★除了but, besides, except, in, save, beyond六个介词后跟that引导的宾语从句外，其他介词都不能。in that是“因为”的意思，其余五个与that搭配都是“除了…”。