-- We don’t think we’ll be able to go mountain-climbing tomorrow.

—______ the weather turns out fine?

A．How come

B．How about

C．What if

D．Why not

血压下降幅度最大的血管是（）

A.主动脉

B.毛细血管

C.静脉

D.小动脉和微动脉

E.微静脉