单项选择题 A self-contained breathing apparatus is used to（）.

单项选择题 A damaged T-Boat that is unable to meet the requirementsof its Certificate of Inspection but is able to travel to a shipyard under its own power should（）.

单项选择题 A bridge over a navigable waterway is being repaired. There is a traveller platform under the bridge’s deck that significantly reduces the vertical clearance. If required by the CG district commander，how will this be indicated at night?（）