林鋒

Now satellites are helping to forecast（預(yù)報(bào)）the weather. They are in space，and they can reach? any part of the world. The satellites take pictures of the atmosphere （大氣）， because this is where the weather forms （形成）. They send these pictures to the weather st ations. So meteorologists （氣象學(xué)家） can see the weather of any part of the world. From the pictures， 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 about 24 or 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）．

跟蹤練習(xí)：

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

Keys：ADD