Any person maintaining a listening watch on a bridge to bridge radio-telephone must be able to（）.

单项选择题Although the parties are entitled to make their contract in any manner that they like，it is usual for them to adopt one of the standard forms and then（）it as they think fit.

A.amend
B.repair
C.improve
D.clear

单项选择题All removals to be reassembled in order（）of repairs.

A.upon commencement
B.on completion
C.before ending
D.after beginning

单项选择题After riveting is completed，the joints on the shell of a vessel are generally made watertight by（）.

A.faying
B.caulking
C.felt or canvas packing
D.red lead

单项选择题A special device that，when fitted into the rotary table，transmits torque to the kelly and simultaneously permits vertical movement of the kelly to make the hole is called a（）.

A.master bushing
B.kelly slips
C.kelly bushing
D.rotary bushing

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

A.make underwater repairs to barges
B.determine if the air in a tank is safe for men
C.enter areas that may contain dangerous fumes or lack oxygen
D.resuscitate an unconscious person