为什么这里用动词原形?He had left the window (open)when he went to bed.用了open却不用opened?

为什么这里用动词原形?He had left the window (open)when he went to bed.用了open却不用opened? had后用动词原形吗 You had better not stand there .翻译,还有为什么动词用原形?是因为not 吗? 为什么练习册中出现had to start+动词原形? You had better+动词原形 He never did anything but watch TV. did之后动词为什么用原形? only后动词为什么用原形He doesn't play sport ,he only watch them on TV.请问watch为什么要用原形? will he be back in two days?,这里为什么加be?一般将来时,will加主语加动词原形,为什么还要加be she had to go shopping yesterday为什么要用动词原形to go而不能用went? 句子all he had to do was……为什么后面接的是动词原形,而不是doing或者to do 新概念英语三里的一个英语语法问题~53课里有一句话 He may gently reprimand an official or even suggest to parliament that a law be altered.这里面be altered这个是什么用法?为什么用be动词原形? 为什么can后面的动词要是原形呢?假如Can he后面的动词为什么是原形? I don't think he could have done such a stupid thing last night,__ A.could he B had he Cdid he这里could不是情态动词,have不是助动词吗?为什么要用did?（答案选C） would rather 后为什么动词原形?因为我常常忘记用动词原形! 为什么这里的动词直接用原形she enjoyed herself making the assistant bring everthing in the window.这里的bring为什么不是to bring或者bringing? 急,it was urgent that he speak to him为什么it was过去式中he speak用动词原形,而不用he spoken或he speaks. he didn't come to school because he (had/have)a high fever.because 后面还是动词原形吗 什么时候用动词原形