题目

如图所示为某高中生想设计的一款防风雨棚，以下不属于其设计限制的是（ ） A . 对相关问题的知识储备 B . 设计对象应达到的标准 C . 使用地点的最大风力大小 D . 发现问题的途径和方法 答案：D阅读理解 　　An altimeter is an instrument used in an airplane to tell the pilot how high he is flying. The altimeter used in most airplanes is a kind of barometer, which, like barometers found in ordinary homes, is a measuring instrument for air atmosphere presses downwards everywhere. At sea level this pressure is more than 14 pounds on every square inch of the surface. The higher you go into the air, the lower the air pressure is. An altimeter measures this air pressure to show the altitude of the airplane, or, how high it is above sea level. But the altimeter does not show how high the plane is above the ground. A plane might, be flying at an altitude(高度)of 15000 feet, but, it would be only a thousand feet or so above the ground if the land in that area happened to be 14000 feet above sea level. 　　The pilot adjusts(调整)his altimeter to the actual sea－level pressure before leaving the airport and then corrects it in flight by new information given to him by radio. He flies high enough to above any mountain he may pass on his course. The barometer altimeter is correct within about 300 feet. 　　Another kind of altimeter, the radio altimeter, makes use of radio reflection. It calculates the height of the flying plane by sending out electrical signals to the surface below and measuring the time required for them to bounce back(弹回). It is correct within 15 feet over water, but is not reliable(可信的)over land. Big planes usually have both kinds of altimeter. 1．The passage mainly introduces ________. [　　] A．the barometer altimeter and air altimeter B．the sea－level altimeter and the radio altimeter C．the barometer altimeter and the radio altimeter D．the air altimeter and the sea－level altimeter 2．Suppose a plane using a radio altimeter is flying 10 000 meters above a highland which is 4 000 meters above sea level. What reading will be given by the altimeter? [　　] A．10000 metersB．4000 meters C．14000 metersD．6000 meters 3．Suppose a plane using both kinds of altimeters is flying over a mountainous area where the land rises and falls very abruptly. The pilot keeps his plane steady at the same height. What kind of reading will you get on each of the altimeters? [　　] A．The readings on both altimeters will remain steady. B．The readings on both altimeters will rise and fall abruptly. C．The reading on the barometer altimeter will rise and fall abruptly, while that on the radio altimeter will remain steady. D．The reading on the radio altimeter will rise and fall abruptly, while that on the barometer altimeter will remain steady: 4．How does the radio altimeter compare with the barometer altimeter when a plane is flying over an ocean? [　　] A．It works fasterB．It works slower C．It is more accurateD．It is less reliable