单项选择题
Water lubricated tailshaft bearings wear,（）
A.the after one is more than forward one B.the forward one is more than after one C.the forward one is the same with after one D.it depends on the type of engine
单项选择题 When sailing in cold zones, the（） should be drained of water.
单项选择题 When sailing in cold zones, the（） should be heated.
单项选择题 When the ships is going to enter into the harbor,（）.
