堤防及土石坝的排渗设施主要有棱体排水、（）、反滤排水沟、排水减压井等。
A.贴坡排水
B.砌石护坡
C.堆石护坡
D.坡面排水沟
参考答案：A
. --- If I were you, I would have accepted the job.
--- I ___________ the offer because it would mean frequent business trip away from my family,
A．turned off
B．turned down
C．turned out
D．turned up
用网喷混凝土加固基坑壁时，基坑开挖深度小于( )m的较完整风化基岩，可直接喷射素混凝土。
A．8
B．10
C．15
D．20
