选择正确的句子,完成对话。  (5')
W : Good 'morning.     （1）    
M: Yes. I'd like a pair of pants for my son.
W: Here are the pants. What colour does your son like?
M: He likes blue.   （2）   
W: Look at this pair. Do you like it?
M:    （3）   Do you have any big pants?
W: Yes. How about this pair?
M :It's nice.   （4）   
W: 80 yuan.
M : Too expensive. What about （7）0 yuan?
W:Well. （5）  . Here you are.
M : Thanks.