（二）【2019 • 浙江省温州市】

Many objects in the universe are invisible, but they send radio waves. The radio telescope thus appeared, and it is considered one of the greatest inventions in the twentieth century. Reber built the world’s first radio telescope in 1937. Ryle and Hewish developed radio telescope systems for the location of weak radio sources, and they shared the Nobel Prize for Physics in 1974.
A radio telescope is usually made up of:
One or more antennas to collect the radio waves. Most antennas are made in the shape of a dish to collect and reflect, the radio waves to the sub-reflector, in the same way as a curved mirror focuses visible light to one point.
A receiver and amplifier to receive the radio waves from the sub-reflector, and make these weak radio waves strong enough to be recorded and turned into electronic signals. To make an amplifier sensitive enough, it is usually cooled to, very low temperatures (e. g. as low as -270℃）.
A recorder to keep a record of the electronic signals. Most: radio telescopes today keep the signals to the computer’s memory disk for astronomers to analyze later.
Radio wavelengths are much longer than those of visible light, and the radio waves from deep space are always weak. To catch Radio wavelengths are much longer than those of visible light, and the radio waves from deep space are always weak. To catch these waves, radio telescopes usually have huge antennas. The sizes of most antennas in use today are around 50 to 300 metres in diameter. The antenna of FAST in Guizhou, China, the latest and largest radio telescope in the world, is 500 metres in diameter, as large as the size of 30 football fields.
To avoid interferences, and keep the telescopes sensitive, radio telescopes are built in places where there are no human radio waves or electronic signals. For example, FAST is 5 kilometres away from the closest village and 25 kilometres away from the nearest town.
Radio telescopes create pictures of the sky, not in visible light, but in radio waves. This is extremely useful, because there are objects that can’t be seen, objects that we wouldn’t even know without radio telescopes.
5. Radio telescopes help collect ___________ from the universe
A. light B. objects C. radio waves D. visible signals
6. Most antennas of radio telescopes are made in the shape of a dish to ___________.
A. make the antennas strong enough B. increase the number of radio waves
C. turn radio waves into electronic signals D. focus radio waves on the sub-reflector
7. The underlined word "interferences" in the passage refers to ___________.
A. the noises made by villagers and animals
B. the sounds from the radios and televisions
C. the people who go to Guizhou to watch FAST work
D. the radio waves and electronic signals from humans
8. What have we done with the help of radio telescopes?
A. We have received pictures of deep space.
B. We have discovered unknown lives in the universe.
C. We have found some unknown objects in the universe.
D. We have turned the radio waves from space into light.
【文章大意】本文主要介绍了无线电天文望远镜，详细介绍了它的发明、构成、工作原理、作用等。
5. C【解析】细节理解题。根据文中的信息A radio telescope is usually made up of：One or more antennas to collect the radio waves.可知，无线天文望远镜帮助收集宇宙中的无线电波，故答案选C。
6. D【解析】细节理解题。根据文中的信息Most antennas are made in the shape of a dish to collect and reflect, the radio waves to the sub-reflector, in the same way as a curved mirror focuses visible light to one point.可知，大多数无线天文望远镜的天线都是碟形的，用来将无线电波聚焦在副反射器上，故答案选D。
7. D【解析】词义猜测题。根据下文and keep the telescopes sensitive, radio telescopes are built in places where there are no human radio waves or electronic signals.可知是为了避免干扰，保持望远镜的灵敏度，无线天文电望远镜建在没有人类无线电波或电子信号的地方。所以"interferences"指的是来自人类的无线电波和电子信号，故答案选D。
8. C【解析】细节理解题。根据文中的信息This is extremely useful, because there are objects that can’t be seen, objects that we wouldn’t even know without radio telescopes.可推知，在无线天文望远镜的帮助下，我们发现了宇宙中一些未知的物体，故答案选C。