问题题干答案解析相关问题热门问题最新问题

问题详情

There are（）operational satellites in the INMARSAT system covering the whole globe except the polar regions.

A、3

B、4

C、8

D、12

时间：2023-03-20 17:05 关键词： GMDSS

答案解析

相关问题

Satellites are an important part of our ordinary lives. For example, the information for weather forecasts is sent by satellite. Some satellites have cameras which take photographs of the Earth to show how clouds are moving. Satellites are also used to connect our international phone calls. Computer connections of the World Wide Web and Internet also use satellites. Many of our TV programs come to us through satellites. Airplane pilots also sometimes use a satellite to help them find their exact location. We use satellites to send television pictures from one part of the world to another. They are usually 35,880 kilometers above the equator. Sometimes we can see a satellite in the sky and it seems to stay in the same place. This is because it is moving around the world at 11,000 kilometers an hour—exactly the same speed that the earth rotates. A satellite must orbit the Earth with its antennae (天线) facing the Earth. Sometimes, it moves away from its orbit, so there are little rockets on it which are used to put the satellite back in the right position. This usually happens about every five or six days. Space is not empty! Every week, more and more satellites are sent into space to orbit the Earth. A satellite usually works for about 10-12 years. Satellites which are broken are sometimes repaired by astronauts or sometimes brought back to Earth to be repaired. Often, very old or broken satellites are left in space to orbit the Earth for a very long time. This is very serious because some satellites use nuclear power (核动力) and they can crash into each other.
As there was a power failure in the hospital, the doctor had to （）operation.
根据下列材料请回答 31～35 题：ANow satellites are helping to forecast the weather．They are in space，and they can reach any part of the world．The satellites take pictures of the atmosphere(大气)，because this is where the weather form．They send these pictures to the weather stations．So meteorologists(气象学家)can see the weather of any part of the world．From the pictures，the scientists can often say how the weather will change．Today，nearly five hundred weather stations in sixty countries receive satellite pictures．When they receive new pictures，the meteorologists compare them with earlier ones．Perhaps they may find that the clouds have changed during the last few hours．This may mean that the weather on the ground may soon change，too．In their next weather forecast，the meteorologists can say this．So the weather satellites are a great help to the meteorologists．Before satellites were invented，the scientists could forecast the weather for about 24 0r 48 hours．Now they can make good forecasts for three or five days．Soon，perhaps，they may be able to forecast the weather for a week or more ahead．第 31 题 Satellites travel______．
There are ____ employees in the company.
There are three members of the family are vividly sketched in the article except[_]