不定式作表语在大部分情况下是不能省略不定式符号to的。然而, 在下列几种情况下, 不定式符号
to可以省略。
1. 当句子主语是被动词 do作谓语的定语从句修饰的all, all that,anything, the only thing ( way) , 或thing 前面有序数词( first, second) 或last 等修饰, 或者是形容词+ 最高级修饰时, to都可以省略
例如：
All you have to do is put it in the toaster and wait till it pops up.
Anything we could do was empty the bottle.
In the evening the only thing he did was read the newspaper.
2. 当主语thing被不定式修饰时, 其表语的不定式符号 to也可以省略
例如：
The thing for you to do is face the facts.
3. 当主语是带有动词 do的由 what引导的主语从句时, 其表语的不定式符号 to可以省略
例如：
What the plan does is ensure a fair pension for all.
4. 当主语 all被以动词say作谓语的定语从句修饰时, 其表语的不定式符号 to也可省略
例如：
All they said is hurry up.
1. 当句子主语是被动词 do作谓语的定语从句修饰的all, all that,anything, the only thing ( way) , 或thing 前面有序数词( first, second) 或last 等修饰, 或者是形容词+ 最高级修饰时, to都可以省略
例如：
All you have to do is put it in the toaster and wait till it pops up.
Anything we could do was empty the bottle.
In the evening the only thing he did was read the newspaper.
2. 当主语thing被不定式修饰时, 其表语的不定式符号 to也可以省略
例如：
The thing for you to do is face the facts.
3. 当主语是带有动词 do的由 what引导的主语从句时, 其表语的不定式符号 to可以省略
例如：
What the plan does is ensure a fair pension for all.
4. 当主语 all被以动词say作谓语的定语从句修饰时, 其表语的不定式符号 to也可省略
例如：
All they said is hurry up.