锰、硅在碳素钢中含量合适均能提高钢的（）。

I like _____ dolphin shows. They are interesting.       [ ]

A. reading        

B. looking        

C. watching      

D. seeing

汽油是重要的自然资源。

Can you tell me ______?[ ]

A. where does he live

B. how did he come here yesterday

C. what his job is

D. that he is good at English

每辆装加自动脱轨制动装置管路的容积（）

A.≤0.8L

B.≤0.9L

C.≤1.0L

D.≤1.5L

我国的领导阶级是（）。

A.农民

B.工人阶级

C.工农联盟

D.先进知识分子