The parking brake system consists of a parking lever, linkage, shut-off valve, light and switch.停放刹车系统的部件不包括：
A.停放刹车手柄;
B.连杆;
C.单向活门;
D.指示灯和电门;
正确答案是C
The parking brake system consists of a parking lever, linkage, shut-off valve, light and switch.停放刹车系统的部件不包括：
A.停放刹车手柄;
B.连杆;
C.单向活门;
D.指示灯和电门;
正确答案是C