[填空题]The photos of Mars taken by satellites are (clear) _____ than those taken from earth.

[填空题]The photos of Mars taken by satellites are (clear) _____ than those taken from earth.

[填空题]The photos of the Mars taken by satellites (卫星) are (clear) （）than those taken from the Earth.

[填空题]The photos of Mars taken by satellites(卫星) are(clear) ______ than those taken from earth.

[单项选择]Communication satellites generally use solar cells as their source of electric power, although some test satellites have used thermoelectric generators.
A. superior
B. authorized
C. former
D. experimental

[单项选择]

Now 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, because this is where the weather form. They send these pictures to the weather stations. So meteorologists 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 or 48 hours. Now they can make good forecasts fo
A. in space
B. in the atmosphere
C. above the ground
D. above space

[单项选择] A

Now 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 or 48
A. in space
B. in the atmosphere
C. above the ground
D. above space

[单项选择]Why did the United States first launch satellites into space a. To improve navigation for warplanes and warships. b. To guide smart bombs that home in on moving targets. c. To collect meteorological data. d. To sense remote volcanic eruptions.

[填空题]With the aid of communications satellites, large newspapers, such as the Wall Street Journal and USA Today, can be printed and distributed nationwide in good time.