下列关于水的物理现象描述正确的是( )。 A．蒸发时放热，结冰时吸热 B．蒸发时

阅读理解。

     Australia is the largest island in the world. It is a little smaller than China. It is in the south of the earth.

Australia is big, but its population is small. The population of Australia is nearly as large as that of Shanghai.

Enough laws have been made to fight against pollution. The cities in Australia have got little air or water

pollution. The sky is blue and the water is clean. You can clearly see fish swimming in the rivers. Plants

grow very well.

     Last month we visited Perth, the biggest city in Western Australia,and went to a wild flowers' exhibition. There we saw a large number of wild flowers we had never seen before. We had a wonderful time. Perth

is famous for its beautiful wild flowers. In spring every year Perth has the wild flowers' exhibition. After

visiting Perth, we spent a day in the countryside. We sat down and had a rest near a path at the foot of a

hill. It was quiet and we enjoyed ourselves. Suddenly we heard bells ringing at the top of the hill. What we saw made us pick up all our things and run back to the car as quickly as we could. There were about three hundred sheep coming towards us down the path.

     Australia is famous for its sheep and kangaroos.After a short drive from any town,you will find yourself in the middle of white sheep. Sheep, sheep, everywhere are sheep.

1. Australia is ______.

A. the largest country in the world

B. larger than China

C. as large as Shanghai  

D. not so large as China

2. Enough laws have been made to ______.

A. increase the population

B. grow more plants

C. fight against pollution

D. show wild flowers

3. Perth is ______.

A. the capital of Australia

B. in the west of Australia

C. in the east of Australia

D. the biggest city in Australia

4. In Perth you may visit the wild flowers' exhibition in ______.

A. October

B. January

C. May

D. July

5. Which of the following sentences is true?

A. All the big cities in Australia are seriously polluted.

B. Australia is famous for its sheep, kangaroos and large population.

C. We ran back to the car because we were in the middle of the white sheep.

D. If you go to the countryside in Australia, you will see a large number of white sheep.

国产200MW机组再热器允许最小流量为额定流量的（）。

A.14%

B.9%

C.5%

D.20% 

(46) History tells us that in ancient Babylon, the cradle of our civilization, the people tried to build a tower that would reach to heaven. But the tower became the tower of Babel, according to the Old Testament, when the people were suddenly caused to speak different languages. In modern New York City, a new tower, that of the United Nations Building, thrusts its shining mass skyward. (47) But the realization of the UN’s aspirations—and with it the hopes of the peoples of the world—is threatened by our contemporary Babel: about three thousand different languages are spoken throughout the world today, without counting the various dialects that confound communication between peoples of the same land.

In China, for example, hundreds of different dialects are spoken; people of some villages have trouble passing the time of day with the inhabitants of the next town. In the new African state of Ghana, five million people speak fifty different dialects. In India more than one hundred languages are spoken, of which only fourteen are recognized as official. To add to the confusion, as the old established empires are broken up and new states are formed, new official tongues spring up at an increasing rate.

In a world made smaller by jet travel, man is still isolated from many of his neighbors by the Babel barrier of multiplying languages. Communication is blocked daily in scores of ways. Travelers find it difficult to know the peoples of other nations. Scientists are often unable to read and benefit from the work being carried on by men of science in other countries. (48) The aims of international trade, of world accord, of meetings between nations, are blocked at every turn; the work of scholars, technologists, and humanists is handicapped. Even in the shining new tower of the United Nations in New York, speeches and discussions have to be translated and printed in the five official UN language—English, French, Spanish, Russian and Chinese. Confusion, delay, suspicion, and hard feelings are the products of the diplomatic Babel.

The chances for world unity are lessened if, in the literal sense of the phrase, we do not speak the same language. (49) We stand in dire need of a common tongue, a language that would cross national barriers, one simple enough to be universally learned by travelers, businessmen, government representatives, scholars, and even by children at school.

Of course, this isn’t a new idea. Just as everyone is against sin, so everyone is for a common language that would further communication between nations. (50) What with one thing and another—our natural state of drift as human beings, our rivalries, resentments, and jealousies as nations—we have up until now failed to take any action. I propose that we stop just talking about it, as Mark Twain said of the weather, and do something about it. We must make the concerted, massive effort it takes to reach agreement on the adoption of a single, common auxiliary tongue.

(50) What with one thing and another—our natural state of drift as human beings, our rivalries, resentments, and jealousies as nations—we have up until now failed to take any action.

在下列关于内力与应力的讨论中，说法（）是正确的。

A.内力是应力的代数和

B.内力是应力的矢量和

C.应力是内力的平均值

D.应力是内力的分布集度

供暖管道必须穿过存在与供暖管道接触能引起燃烧或爆炸的气体、蒸气或粉尘的房间时，与可燃物之间保持的距离应满足相关要求。下列要求中正确的是（）。

A.当温度大于100℃时，此距离不小于50mm或采用不燃材料隔热

B.当温度大于100℃时，此距离大于50mm且小于100mm或采用不燃材料隔热

C.当温度不大于100℃时，此距离不小于50mm或采用不燃材料隔热

D.当温度不大于100℃时，此距离不小于100mm或采用不燃材料隔热