This problem is too difficult .Can you show me_____,George?—Sure.

A.what to work out    B.to work it out    C.how to work it out    D.to work out it
翻译句子
对于灾区的孩子来说,祖国就是他们的家
The homeland is______  ______the children in the disaster.
2.你还想问我其他什么吗?
______ _____do you want to ask me?
3.你听说过哪些类型的事故?
What kind of accidents do you _____ _____?
4.他对上网聊天感兴趣吗?
Is he _____ _____ chatting online?