为了消除邮政支局的安全隐患，遇上雨雪天气，应当在营业厅门口放置（）。 A.雨伞 B.

—Why are you so frustrated, Ben?

—I was late for class again. I’m afraid Miss Li will be _________ me.

A．busy with

B．angry with

C．friendly to

D．proud of

根据所给情景选择合适的句子。

1.你想让别人告诉你4+12等于多少，你会说：    [ ]

A. What's four and twelve?    

B. What's five plus twelve?  

C. Four plus twelve is sixteen.

2.别人询问你11 +9等于多少时，你可以这样回答：   [ ]

A. Eleven minus nine is two.    

B. Eleven plus nine is nineteen.  

C. Sorry, I don't know.

3.当别人同答问题错了，你可以说： [ ]

A. Sorry, you're wrong.    

B. All right.  

C. You're right.

4.当别人不小心撞到你向你道歉时，你会说：   [ ]

A. Oh, I’m sorry.    

B. All right.  

C. That's all right.

单元机组协调控制投入的顺序如何？

何为十字丝视差？如何消除？

加热短预热段炉顶下压的目的是提高流速增加（）传热，降低出炉烟气温度。

A.传导

B.对流

C.辐射