单项选择题
Blocks and falls used as lifeboat gear must be designed with a minimum safety factor of（）.
A.4，based on the breaking strength B.5，based on the maximum allowable stress C.6，based on the maximum working load D.8，based on the normal working load
单项选择题 BHP stands for the（）of the main engine.
单项选择题 Before starting to hoist provisions，which should be checked?（）
单项选择题 Before operating a non-oceangoing ship greater than 100 gross tons it must have a fixed piping system to discharge oily mixtures ashore. This system must include（）.
