对重的作用是()
A.平衡轿厢重量
B.减少能量消耗
C.构成合适的曳引力
D.提高电梯速度
参考答案:A, B, C
-I can’t believe that you _______ that old trick.
-Yes, I was stupid enough.
A.dealt with
B.fell for
C.took in
D.came across
自动驾驶仪由哪几部分组成?有哪几种工作状态?