补全对话

A: What do you think of the weather in summer in Guilin?

B:     1     But it's cooler than that in the cities in the south.

A: Oh, do you like rainy days?

B:     2     I like watching it raining and the rain drops falling on me make me cool and relaxed.

A:     3  

B: No, there aren't. But usually there are strong winds blowing in spring and autumn.

A:     4  

B: Yes, it does. The rain usually comes after the hottest weather and lasts for several days. 

A:     5  

B: No. It hardly snows.

A: I think it's great to live there.

A. It's very hot.  

B. Does it often rain in Guilin?  

C. Are there lots of winds in summer?  

D. Does it snow in winter?  

E. Yes, very much.

旁路系统的作用是什么？