经碱水加热可生成无酯键的醇胺型水解产物的生物碱是（） A.药根碱 B.次乌头碱 C.

       Now satellites are   1   to forecast (预报) the weather. They are in space, and they can   2   any
part of the world. The satellites take pictures of the atmosphere(大气) ,  3   this is where the weather
forms(形成). They send these   4   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   5   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  6   . Perhaps they may find that the
 clouds have changed during the last few hours. This may mean that the   7   on the ground may soon
change, too . In their next weather forecast , the meteorologists can say this. So theweather satellites are
a great   8   to the meteorologists.  9   satellites were invented, the scientists could forecast the weather
for about 24 or 48 hours. Now they can make good forecasts for three or fivedays. Soon , perhaps ,
they may   10   forecast the weather for a week or more ahead(提前) .