My brother          with his friends tomorrow if it          .            [ ]

A. is going to hike; won't rain            

B. is going hiking; doesn't rain            

C. will go hiking; won't rain            

D. goes hiking; doesn't rain

静止阳极X线管，下列哪个是错误的（）

A.真空度

B.灯丝

C.阳极轴承

D.集射罩

E.阳极靶角度