办公用房室内净高不应低于2.5米，人均使用面积不宜小于（）平方米。 A.2 B.3

解方程．

30%x=120

x+35%x=240

x-60%x=160

50%x-33%x=34

120x-20x=40

x+130%x=460．

用所给词语的适当形式填空。

1. Exercising every day is good for your _____ ( health ).

2. He likes fishing. He goes fishing _____ ( two )a week.

3. I don't like milk, but my mother wants me _____ ( drink ) it every morning.

4. In our school most _____ ( student ) get to school by bike.

5. Tony never exercises. So I think he is kind of _____ ( health ).

6. I eat more vegetables and less meat. I think my _____ ( eat ) habits are pretty good.

7. She enjoys _____ ( surf ) Internet on weekends.

8. How often do you go _____ ( skateboard ) with your friends?

9. Look! Here _____ ( be ) some money for you.

10. How many _____ ( people) are there in your family?

11. A lot of vegetables can help you keep _____ ( health ).

12. I am not sure. He may _____ ( be ) a reporter.

13. I think my healthy lifestyle helps me _____ ( get ) good grades.

14. Mike with his friends _____ ( exercise ) every day.

15. This dictionary is _____ ( difference ) from that one.

香港、澳门回归后，已分别建立（　　）

A．特别行政区

B．经济特区

C．自治区

D．直辖市

油罐进油时，浮顶油罐的安全高度为浮船倒向装置轨道上限（）

A.平齐处

B.以下10cm

C.以下20cm

D.以下30cm

阅读材料，回答下列问题。

材料一：自然灾害对人类社会所造成的危害往往是触目惊心的。它们之中既有地震、泥石流、台风、洪水等突发性灾害；也有地面沉降、土地沙漠化、干旱等在较长时间中才能逐渐显现的渐变性灾害；还有水体污染、水土流失、酸雨等人类活动导致的环境灾害。对抗自然灾害还要以预防为主。

材料二：无论是汶川大地震，还是玉树地震或是舟曲的泥石流灾害，每次灾害发生后人们都能看到在党的坚强领导下，政府科学调度，抢救被困人员，转移安置群众等各项工作在有力有序进行。我们的救灾应急机制更加健全，灾后重建更加科学。频繁的自然灾害让我们屡遭创伤和苦难，中国却没有被压倒，中国挺起了她不屈的脊梁！

材料中“不屈的脊梁”指的是什么？中国为什么必须“挺起不屈的脊梁”？