赞题库-背景图

单项选择题

Air cannot ______,but it is all around us.

A．is seen
B．see
C．be seen

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热门试题

单项选择题Billy got ______ as a waiter in a restaurant.

A．a work
B．a job (工作，职责)
C．a piece of work

单项选择题As soon as you ______ I'll tell you the news.

A．are coming
B．will come
C．come