在石料缺乏、地基承载力较低的路堤地段宜采用()挡土墙。
A.重力式
B.短卸荷板式
C.扶壁式
D.锚杆
参考答案:C
My friend asked me to go for _____ walk, but I don't think I've got _____ energy. [ ]
A a; /
B. the; the
C. / ; the
D. a; the
给水泵的作用和要求是什么?