单项选择题
When instructing a crew member concerning the right way to lift a weight，you would instruct him to（）.
A.Arch the back to add strength to the muscles B.Bend his knees and lift with his legs C.Bend his back and stoop D.Bend his back and stoop with arms straight
单项选择题 When discharging oil from an oil tanker the instantaneous rate（）60 liters per nautical mile.
单项选择题 When discharging an oil cargo，the first consideration is to（）.
单项选择题 What is/are the advantage（s）of cranes over conventional cargo booms（）.
