Now satellites are helping to forecast (预报) 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
forms (形成). 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 24or 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 (提前).

1. Satellites travel ____. 　　

A. in space
B. above space
C. above the ground
D. in the atmosphere

2. Why do we use the weather satellites to take pictures of the atmosphere?Because ____. 　　

A. clouds form there
B. the weather forms there 　　
C. the weather satellites can do it easily
D. the pictures can forecast the weather

3. Meteorologists forecast the weather ____. 　　

A. without studying satellite pictures 　　
B. before they receive satellite pictures 　　
C. when they have received satellite pictures 　
D. after they have compared the new satellite pictures with the earlier ones

4. Maybe we'll soon be able to forecast the weather for _____.

A. one day
B. two days 　
C. five days
D. seven days or even longer