单选题
We all know that it is possible for ordinary people to make their homes on the equator (赤道), although often they may feel uncomfortably hot there. Millions do it. But as for the North Pole (北极)--we know that it is not only a dangerously cold place, but that people like you and me would find it quite impossible to live there. At the present time only the scientists and explorers can do so, and they use special equipment. Men had been traveling across and around the equator on wheels, on their feet or in ships for thousands of years; but only a few men, with great difficulty and in very recent time, have ever crossed the ice to the North Pole. So it may surprise you to learn that, when traveling by air, it is really safer to fly over the North Pole than over the equator. Of course, this is not true about landings in the polar region (which passenger aeroplanes do not make), but the weather, if we are flying at a height of 5000 meters above the Pole, is a delight. At 4 000 meters and More above the earth you can always be sure that you will not see a cloud in the sky as far as the eye can reach. In the tropics (热带), on the other hand, you are not certain to keep clear of bad weather even at such heights as 18 000 or 20 000 meters. Aeroplanes can't climb as high or as quickly in cold air as in warm air. Nor can clouds. In practice, this is an advantage to the aeroplane, which is already at a good height when it reaches the polar region and so does not need to climb, while at the same time cold air keeps the clouds down low.
单选题
"Millions do it. " In this sentence "do it" refers to ______. A. feeling uncomfortably hot on the equator B. flying over the North Pole C. flying over the equator D. making homes on the equator
【正确答案】
D
【答案解析】[解析] 细节题。第一段提到：We all know that it is possible for ordinary people to make their homes on the equator，although often they may feel uncomfortably hot there．Millions do it．根据动词do，可知它代替的是前面出现的某个动作，通读全句，只有D最合适。
单选题
The polar region is ______. A. a good place to land at by aeroplane B. a good place to fly over C. a bad place to fly over D. a good place to live in
【正确答案】
B
【答案解析】[解析] 细节题。第一段提到So it may surprise you to learn that，when traveling by air，it is really safer to fly over the North Pole than over the equator．因此你可能会惊讶地得知，乘坐飞机飞越北极比飞越赤道更安全。因此B正确。
单选题
It is a delight to fly at the Pole because there ______. A. planes fly higher than at the equator B. the eyes can reach about 4 000 meters C. planes are clear of bad weather D. planes fly more quickly than at the equator
单选题
Aeroplanes can climb quickly ______. A. in warm air B. in cold air C. when it reaches the polar region D. only when the clouds are down low
【正确答案】
A
【答案解析】[解析] 细节题。第二段开头提到：Aeroplanes can’t climb as high or as quickly in cold air as in warm air．A符合句意。
单选题
Aeroplanes usually do not need to climb quickly or fly high in the polar region because ______. A. they do not land there B. there are no clouds at all C. they can cross the ice with special equipment D. it is very cold