句子what I can do is to study hard.为什么要有to?

What can I do>>>I can't use chinese now! It is really?I can't believe.what do you think so ?这是什么意思啊? 句子what I can do is to study hard.为什么要有to? what do I can do it这个句子存在不存在! Don't you know What I can do?的What I can do与句子What can I do?为什么是一种意思的两种表达方式?这中间该怎么区分,是语法还是什么? I don't konw what i can do here. To my want,I can't do anything.I can do what ,who can tell me? I don't know what can I do 还是 I don't konw what I can do what can I do what can I do what can I do? what can i do 速求英语句子帮忙解读下.That I can't choose how I feel,but I can choose what I do about it 英语翻译i know the thing.变一般疑问句do you know the thing.变特殊疑问句who do know the thing.哪这个句子who is to say I can't?能不能写成who do to say what i can't?为什么who后面是be动词is? do what I can 是个什么句子,后面是不是一定要有do (即do what I can do）? 同义句:I don't know what I can do .转换：I don't know what ( ) ( ). now.feel very sad,i don‘t know i can do what who can tell me what can i do dame it!why can't you just shut up!I can't say something what I want?nothing is wrong!是什么意dame it!why can't you just shut up!I can't say something what I want?nothing is wrong!I don't think that I break the rules!how can you do that can you t