对于挖方路基上边坡发生的滑坡，应修筑一条或数条环形( )。
A．排水沟
B．拦水带
C．急流槽
D．截水沟
参考答案：D
_______John likes Mary, he does not want her to be his wife.
A．As long as
B．Much as
C．Before of
D．in spite of
在活塞式发动机飞机上，为除冰带充气的气源是（）
A、叶片泵
B、齿轮泵
C、柱塞泵
D、离心泵
