单项选择题 A vessel is approaching from dead ahead.Both of her sidelights are visible and her range lights are in line.Which of the following could you do first（）.

单项选择题 When a pushing vessel and a vessel being pushed are rigidly connected in a composite unit，they shall be regarded as（）.

单项选择题 What determines if a vessel is restricted in her ability to maneuver?（）.