---Can you tell me something about metal ?
---Metal making machines and many other things .
A. used to
B. is used for
C. is used as
D. is used to
网友回答
A. used to
(答案→)B. is used for
C. is used as
D. is used to
解析:此题重点考查be used to doing sth、used to do sth 、be used as和be used for doing sth四个个句型结构的区别和意义。be used to doing sth是习惯做某事,used to do sth表示过去常常做某事,现在不做了。be used as是把…用作…be used for doing sth表示被用来做某事。