只能用不能用的情况

只能用whether不能用if的情况只能用whether不能用if的情况如下：

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whether可以放在介词后面作宾语，而if不可以，只能用whether主要有以下几种情形：
1、强调两方面的选择，特别是句中有or、not时。
例：Let me know whether you can come or not.
2、宾语从句前置时。
例：Whether this is true I can't say.
3、引导主语、表语、同位语从句时。
例：Whether the football game will be played depends on the weather.
The question is whether he can do it.
The question whether we should go with them must be decided at once.
4、在介词之后作介词的宾语时。
例：I haven't settled the question of whether I'll go back home.
【只能用不能用的情况】5、在不定式前与不定式一起组成词组时。
例：Whether to go or stay is still a question.
6、在discuss、decide等动词后作宾语时。
例：We discussed whether we should go there by plane.
定语从句只能用that不能用which的六种情况是什么？定语从句只能用that而不能用which的六种情况：
1、如果先行词是all, much, anything, something, nothing, everything, little, none等不定代词,关系代词一般只用that,不用which 。如：
All that can be done has been done.
能做的都已经做了。
He will tell you everything that he heard about it.
他将告诉你他所听到的关于这件事的一切。
2、当先行词被all, every, no, some, any, little, much所修饰时，只能用that，如：
There is little work that is fit for you.
没什么工作运合你做。
I have eaten all the food that is left.
我把剩下的所有食物都吃了。

3、先行词是序数词或最高级形容词时，或者先行词被序数词（包括last，next)、最高级形容词及the only, the very等修饰时。如：

This is the first film that I have seen since I came here.
这是我到这里后所看的第一场电影。
This is the best that has been used against pollution.
这是用来防止污染的最好办法。
This is the very book that I am looking for.
这正是我一直在寻找的那本书。

4、先行词包括人和物时，关系代词应该用that 。如：

They often talk about the people and the things that they are interested in.
他们常常谈论那些他们感兴趣的人和事。
Luxun and his works that we are familiar with are considered great.
人们认为我们所熟识的鲁迅及其作品都很伟大。

5、当主句是以who或which升头的疑问句时，为了避免重复，多用that导。如：

Which is the house that caught fire last night
昨晚失火的是哪座房子？
Who is the lady that is playing the piano
在弹钢琴的那位小姐是谁？
6、当先行词在定语从句中作表语时，只能用that 。如：
This is a book that I have been looking for since last week.
这就是那本自上周以来我一直在寻找的书。

只能用which不能用that的情况1、引导非限制性定语从句时。2、当关系词前有介词时。3、在一个句子中有两个定语从句，其中一个定语从句的关系代词用了that，另一个宜用which.4、当关系代词后面有插入语时。5、先行词为that时。
只用which不用that的情况1、引导非限制性定语从句时。例如：
Bamboo is hollow, which makes it light.竹子是空心的，这使得他很轻。
2、当关系词前有介词时。例如：
This is the room in which Chairman Mao once lived.这就是毛主席曾经住过的地方。
3、在一个句子中有两个定语从句，其中一个定语从句的关系代词用了that, 另一个宜用which.例如：
Let me show you the novel that I borrowed from the library which was newly open to us.我来给你看我从新开的图书馆里借来的那本小说。
4、当关系代词后面有插入语时。例如：
Here is the English grammar which, as I have told you, will help improve your English.这就是我跟你说过的会有助于你学好英语的那本英语语法书。
5、先行词为that时。例如：
The clock is that which can tell us the time.钟是报时的装置。
宾语从句只能用whether不能用if的情况只能用whether，不能用if引导的宾语从句
1、在带to的不定式前
eg.We decided whether to help him.
我们决定去帮他。
2、在介词的后面
eg.I’m thinking of whether we should help him.
我正在想是否要帮他。
3、在动词后面的宾语从句时
eg. We discussed whether we should help him.
我们就是否帮助他进行了讨论。
4、直接与or not连用时
eg. I can’t say whether or not they will help him.
我不能说他们是否会帮助他。
扩展资料
只能用if的情况：
1、if引导的表假设的从句：
eg. He will be saved if we help him.
如果我们救他，他将被获救。
2、if引导的表否定的从句:
eg. He asked if I didn’t help him.
他问我是否没有帮助他。
3、直接使用even if和as if
eg. He talks as if he has known all about it.
他说起话来好像已经知道了一切。
什么情况下只能用that不能用which定语从句中只能用that ，不能用which的情况：
1 先行词有序数词，形容词最高级时或本身是序数词，基数词，形容词最高级时只能用that
2当被修饰的先行词为 all , any
.much , many , everything ,anything , none ,the one 等不定代词时。
3 当先行词被the ony ,the
very , the same ,the last , little ,few 等修饰时
4 当先行词里同时有人和物时。
5 当主句是以who / which 引导的特殊疑问句时。