The disinfection of various compartments in a vessel by filling with a gaseous agent to destroy rats and all insects pests which act as germ carriers means（）.

Backing means the wind（）.A.is changing clockwise in dir...

单项选择题Backing means the wind（）.

When a feature remains in its existing charted position...

单项选择题When a feature remains in its existing charted position but has a change of characteristic,（）command is used on a chart.

Any action to avoid collision shall,if the circumstance...

单项选择题Any action to avoid collision shall,if the circumstances of the case admit,（）,made in ample time and with due regard to the observance of good seamanship.