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举一反三
【单选题】The Exploding Lakes of Cameroon What comes to mind when youthink of a lake? You probably imagine a pretty scene with bue water, brds, and fish. FOr the people in the northwestern Cameroon, however,the...
A.
Water will flow down the hills.
B.
Poisonous gases will bereleased suddenly.
C.
A strong wind will rise from the lakes.
D.
The volcanoes will come to life.
【多选题】混凝土坝防渗帷幕应符合下列( )要求。
A.
减小坝基和绕坝渗漏，防止渗漏水流对坝基及两岸边坡稳定产生不利影响
B.
防止在坝基软弱结构面、断层破碎带、岩体裂隙充填物以及抗渗性能差的岩层中产生渗透破坏
C.
在帷幕和坝基排水的共同作用下使坝基扬压力和坝基渗漏量降至允许值以内
D.
具有连续性和足够的耐久性