对活塞销的主要要求有________。I．强度高II．刚性好III．抗高温腐蚀IV．耐磨损V．表面光洁VI．抗低温腐蚀
A. II+III+IV+VI
B. I+II+IV+V
C. III+IV+V+VI
D. II+III+V+VI
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_______means the level for which appropriate additional protective security measures shall
A. Security level 1
B. Security level 2
C. Security level 3
D. Security level 4
Which of the listed fire extinguishers cannot be easily recharged aboard ship？
A. Soda acid
B. Carbon dioxide
C. Dry chemical
D. cartridge-operated Foam
The mode of control employed by an alarm circuit is a
A. two position control
B. single speed floating control
C. proportional speed floating control
D. reset control
当价格水平上升，实际利率________，同时实际GDP的需求量________。
A. 上升；增加
B. 上升；减少
C. 下降；增加
D. 下降；减少
E. 不变；不变
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