1. [单选题]离心泵转速降低时( )。
A. 流量减少
B. 有效汽蚀余量增加
C. 必需汽蚀余量减少
D. 以上全部
2. [单选题]在下列何种情况下，可认为火势已被控制住：
A. 灭火剂正在火床上施放，并已开始有效地把火冷却。
B. 火的主体已经暗下去。
C. 所有火势可能扩散的路线都已加以检查或保护。
D. 以上都对。
3. [单选题]Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?
A. Baffle plates that have been bent during prior removal
B. Leaks m the cooler tube nest
C. Operating the engine while maintaining a high sea water outlet temperature
D. A punctured sea water strainer supplying cooling water to the heat exchanger
4. [单选题]落水者(fall in water person)体温下降的速度取决于几个条件：
A. 2个
B. 3个
C. 4个
D. 5个
5. [单选题]The______Convention is the first to establish basic requirements on training, certification and watch-keeping for seafarers on an international level.
A. STCW78
B. STCW95
C. SOLAS74
D. SOLAS88
