机械效率大表示的意思是[ ]

A.机械做的总功多

B.机械做的有用功多

C.总功一定时，机械做的额外功少

D.额外功在总功中占的比例小

根据提示完成句子。

1. She ________ (穿上) her coat and went out. (put)

2. We should be allowed ________ (自己作决定). (make)

3. More attention ________ (应放在) the needs of the poor. (pay)

4. Great changes ________ (发生了) in my hometown these years. (take)

5. I don't know ________ (他与……相处得怎样) with the others now. (get)