Was the door of the room _______ the whole day?    [ ]

A. remained opening                          

B. allowed open   

C. kept opened                                

D. left open

天线应在避雷针保护区域内，避雷针保护区域是避雷针顶点下倾（）范围内。

A.30°

B.40°

C.50°

D.60°