作业帮but 的具体用法是什么?He did nothing but stay idel.He had no choice but to give in.一句有to,一句没有to
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but 的具体用法是什么?
He did nothing but stay idel.
He had no choice but to give in.
一句有to,一句没有to
我告诉你个口诀：“有do,无to；无do,有to”,
在but的前面如果出现了do,did,does的话,but 后面的to就可以省略,
另外,此类的用法,还有except 和主系表结构,也是一样的.
e.g.They did nothing but wait.
She did nothing except look at the photo.
反过来,but的前面如果没有do,did,does,but 后面就用to
e.g.There is no choice but to wait.
主系表句型里：主语不带“do”,表语则用to
主语带“do”,表语的 to可用可不用
e.g.Your job is to reply emails from the customers.
The only thing I can do now is (to) go on by myself.
主语里的定语从句有个do
but 作介词 ， “除了。。。”
当主句中存在do 动词的任何形式， 介词but 后就省去to, 而只接do
I couldn't do anything but sleep
I did nothing but wait
He had nothing to do but cry.
而I had no choice but to sleep
do ...
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but 作介词 ， “除了。。。”
当主句中存在do 动词的任何形式， 介词but 后就省去to, 而只接do
I couldn't do anything but sleep
I did nothing but wait
He had nothing to do but cry.
而I had no choice but to sleep
do 的现在时形式，过去式形式，完成时形式（have done, had done....)
将来时will do ,would do //
情态动词后
记住：只是do动词，不能是其他行为动词
我给你的例句，前3个，有do
后一个，无do,; 那个had 属其他动词
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