单项选择题
The boom stops are installed on an offshore crane to（）.
A.prevent the boom from being raised too high B.prevent the boom from swinging C.support the boom when not in use D.prevent the boom from being lowered
单项选择题 The annual survey for endorsement of a Load Line Certificate must be held within（）.
单项选择题 The angle between the flukes and the shank of an anchor is called the（）.
单项选择题 The angle at which the anchor flukes penetrate the soil is the（）.
