单项选择题
When visibility is restricted（），we can say it is restricted visibility.
A.by long distance B.by the darkness at night C.by a vessel in front D.by fog or falling snow
单项选择题 When underway in a channel，you should keep to the（）.
单项选择题 When underway in a channel，you should if safe and practicable（）.
单项选择题 When two vessels are in sight of one another and NOT in or near an area of restricted visibility，any of the following signals may be given EXCEPT（）.
