题目

太阳能飞机以太阳辐射作为推进能源的飞机。太阳能飞机的动力装置由太阳能电池组、直流电动机、减速器、螺旋桨和控制装置组成。由于太阳辐射的能量密度小，为了获得足够的能量，飞机上应有较大的摄取阳光的表面积，以便铺设太阳电池，因此太阳能飞机的机翼面积较大。请回答下列问题： （1） 制成该飞机的机体材料可以是_____。（在A、B、C中选填） A . 韧性好、硬度大的锰钢 B . 强度好、密度小的铝合金 C . 抗腐蚀性好的不锈钢 We can stay young forever. That is the message Dr. Shen Ziyin wants to give the world. And the Chinese doctor claims that he has found an answer to the problems of aging.His solution is a herbal medicine to slow the process of aging.Dr. Shen Ziyin has been trained in Western medicine. At the same time he studied traditional Chinese medicine. And, he has been working for the past forty years to put together the best of both and find a cure for aging. He has taken a hint from the ancient Chinese medicine system called “shen”.According to Shen, it is the kidney which adjusts the functioning of the body as well as its aging process. It is responsible for the level of activity that the human bodies go through. Studies conducted by Dr. Shen show that herbal medicine based on the shen system slow the aging process, says a report in The Telegraph newspaper.We notice that when people grow old, they have reduced strength, loss of hair, backache, weakness in general, and wrinkles, among others. This happens because when people grow old, their bodies produce T-cells. These T-cells contain a particular substance called Fas. Fas makes the cells in the body destruct themselves.So the only way to slow down aging is to slow the production of T-cells in the body. This can happen if people eat low calorie food. Then the body is not active enough to produce extra T-cells. But, is going hungry all the time a good price to pay for staying young?This is where Dr. Shen’s herbal medicine comes in. But how effective it will be, only time can tell.1. How did Dr. Shen find the solution to the problem of aging?A. By studying Western medicine.B. By learning traditional Chinese medicine.C. By doing research on both Western and Chinese people.D. By combining both Western and Chinese medicine.2.What plays the most important role in keeping people young according to Shen?A. Medical treatment.B. People’s good kidney.C. Level of people’s activity.D. Positive life attitude.3.The reason why people become old is that _________.A. their bodies are unable to fight diseasesB. their bodies produce T-cellsC. they have reduced strength, loss of hairD. they become weaker and weaker4.We can probably learn from the passage that _________.A. people should try to quicken the production of T-cells in the bodyB. the more Chinese herbal medicine people drink, the better for healthC. it remains unknown how effective Dr. Shen’s herbal medicine isD. producing more low calorie food allows people to keep young