单项选择题
A.clean off any mud that may have accumulated on the chain
B.engage or disengage the wildcat
C.fairlead the chain from the hawse pipe to the wildcat
D.prevent the chain from fouling the wildcat
单项选择题 The Pilotage-quarantine anchorage，（）between Damen Dao and Qingshan Dao，is defined by the lines（）the given points.
单项选择题 The most doubtful and unpredictable factor in a mooring system is the（）.
单项选择题 The lockmaster has given you permission to tie off on the lower guide wall to wait your turn to lock through. What should you be most concerned with? （）