抛物面透镜与球面透镜相比，其（）得以提高。A.色温 B.显色指数 C.清晰度 D.照

As a boy of six,           .

A．Tim’s parents asked him to play the piano every day.

B．Tim and his parents would play the piano together.

C．Tim had to practice playing the piano every day.

D．to learn playing the piano is too hard for Tim.

You needn’t have ________ the speaker when he was speaking; there was enough time afterwards for you to ask questions.

A．affected

B．disturbed

C．involved

D．interrupted

二战以来西方国家政府首脑权力不断强化的原因是什么？

火力发电厂主厂房室外疏散楼梯的净宽不应小于（）m，楼梯坡度不应大于45°，楼梯栏杆高度不应低于1.1m。

A、0.7

B、0.8

C、0.9

D、1.1

----Have you ________ some new ideas.    

----- Yeah. I’ll tell you later.[ ]

A. come about    

B. come into    

C. come up with  

D. come out with