单项选择题
The strake on each side of the keel is called a（）.
A.sheer strake B.gatewood strake C.insulation strake D.garboard strake
单项选择题 The riding pawl is（）.
单项选择题 The purpose of cant frames in steel vessels is（）.
单项选择题 The platform that supports the derrickman when tripping pipe is called the（）.
