车辆制动装置在三通阀或分配阀装车之前必须对制动主管和支管进行（）后方可连接组装。
参考答案：清楚锈垢
The number of people present at the concert was than expected. There were many tickets left. [ ]
A. much smaller
B. much more
C. much larger
D. many more
可以按因素法编制弹性利润预算的企业有( )。
A．经营单一品种或采用分算法的企业B．经营多品种的企业C．国营及集体所有制企业D．任何类型的企业
