热交换器应以工作压力的( )倍做水压试验。
A.1.2
B.1.5
C.1.8
D.2.0
参考答案:B
The _____ soldiers fight against the enemies _____. [ ]
A. brave, brave
B. brave, bravely
C. bravely, brave
D. bravely, bravely
发动机空滤进行清洗保养后,在滤筒安装前应做到哪些工作?