正常输尿管有几个生理性狭窄（）
A.3个狭窄
B.2个狭窄
C.5个狭窄
D.4个狭窄
E.6个狭窄
参考答案：A
I’m sure that your letter will get _____attention. They know you’re waiting for the reply.
A．continued
B．immediate
C．careful
D．general
停炉（）小时后，方可对锅炉自然通风冷却
