下面关于排水明渠表述正确的是()。
A、采用矩形、梯形
B、断面底宽不小于0.3m
C、采用1:0.75-1:1的边坡
D、不能采用自然弧形
参考答案:A, B, C
You are excellent, but we have no of teachers for the time being. [ ]
A. use
B. lack
C. result
D. want