单项选择题
The self-contained breathing device should not be used in which situation（）.
A.Oxygen deficient spaces B.Compartments containing poisonous vapors C.Fighting fires that produce heavy smoke D.Underwater search
单项选择题 The rescuer can best provide an airtight seal during mouth-to-mouth resuscitation by pinching the victim’s nostrils and（）.
单项选择题 The key to rescuing a man overboard is（）.
单项选择题 The indication of a slipping anchor is a（n）（）.
