下图为某地等高线图，若甲地为一展望台，则①～⑥六个点中有哪些点最有可能为甲地视线的“死角”（）
A.①②③
B.②④⑥
C.①③⑤
D.④⑤⑥
参考答案：D
If we _______ adequate preparations, the conference wouldn't have been so successful.[ ]
A. haven't made
B. wouldn't make
C. didn't make
D. hadn't made
垃圾场覆盖可根据覆盖的要求和作用分为几种，但一般不包括下述( )。
A．(A) 日覆盖
B．(B) 季节覆盖
C．(C) 中间覆盖
D．(D) 最终覆盖
