单项选择题
For a given weight of cargo，the stress on the heel block of a cargo boom（）.
A.increases as the cargo closes the head while hoisting B.increases if the cargo runner is doubled up C.decreases as the boom is topped to a greater angle D.is determined by the thrust stresses on the boom
单项选择题 Bonding cables are used during cargo transfer to（）.
单项选择题 Backstays are（）.
单项选择题 All the damage and shortage，（）those incurred after discharge and before delivery to receivers，should be noted in the discharging report.
