同压力弹簧离合器相比，膜片弹簧离合器有（）优点。
A.维修方便
B.踏板力较小
C.工作方式简便
D.无离合器间隙
参考答案：B
不准许销售的农产品有哪几类？
—Must I get up before seven o’clock tomorrow?
—_______. It is Sunday tomorrow, you can have a good rest.
A. Yes, you must B. No, you don’t have C. No, you needn’t
