AMVER is a system which provides（）.

单项选择题A yellow signal，floating in the air from a parachute，about 300 feet above the water，indicates that a submarine（）.

A.will be coming to periscope depth
B.will be coming to the surface
C.is on the bottom in distress
D.is in distress and will try to surface

单项选择题A rigid replica of the International Code flag A may be shown by a vessel（）.

A.pulling a submarine cable
B.engaged in diving operations
C.engaged in underway replenishment
D.transferring explosives

单项选择题A message by flashing light consists of the call，the text，the ending，and the（）.

A.identity
B.time of origin
C.reply
D.procedure code

单项选择题A message by flashing light consists of the call，the identity，the ending，and the（）.

A.reply
B.text
C.time
D.answer

单项选择题“How do you read?” “I read you with signal strength one”（）.

A.poor
B.bad
C.fair
D.good