单项选择题
A rigid lifesaving device designed to support survivors in the water is a（）.
A.rigid liferaft B.life float C.inflatable liferaft D.survival capsule
单项选择题 A liferaft which has inflated bottom-up on the water（）.
单项选择题 A life line must be connected to the liferaft（）.
单项选择题 A chock（）.
