泡沫比例混合器分为()比例混合器。
A.环泵式
B.压力平衡式
C.独立式
D.一体式
参考答案:A, B
If you are able to talk to a friend over the telephone, you feel that you are close ____ the actual
distance is not shortened. [ ]
A. so long as
B. if
C. even if
D. as
闪烁的红灯表示()。
A、减速慢行
B、顺利通行
C、准备停车