At sea, we usually use() to provide hot water.
A. a heater
B. an exhaust gas boiler
C. an engine
_______ is NOT included in the factors used in analyzing vowels。
A. Position of the tongue
B. Shape of lips
C. Openness of the mouth
D. Openness of the vocal cords
核动力厂人员必须接受处理()的教育。
A. 运行瞬变
B. 预计运行事件
C. 设计基准事故
D. 超设计基准事故