限速器的选用应符合电梯额定速度的要求，否则将起不到（）。
A.作用
B.安全作用
C.效果
D.安全效果
参考答案：B
用正确的单词填空。
1. The people ______ travel all over the world think China is a beautiful country.
2. I can't say anything ______ moves us deeply.
3. Paper is made ______ wood.
4. The trees can stop the flood from ______ (wash) the earth away.
5. By the end of last term, we ______ (study) three thousand words.
6. You must practise ______ (play) the piano every day.
7. Edison was a great American ______ (invent).
8. He hasn't enough ______ (经验) for the job.
9. It's good to tell ______ (true).
10. You'd better ______ (not go) to the supermarket.
