（）the rise and fall of the tide.

单项选择题Please light the pilot lamp.（）up and （） down. （）

A. White；red
B. Red； white
C. Red； green
D. Green ；red

单项选择题If we have a pilot on board , we should take down （） and hoist （） .（）

A. flag H ； flag G
B. flag G； flag H
C. flag H ； flag Q
D. flag G； flag Q

单项选择题When the anchor reaches the bottom ,hoist the anchor （）by day.

A.ball
B.flag
C.light
D.lamp

单项选择题Letter “G” shows that“ （）”.

A. I have a pilot on board
B. I require a pilot.
C. I have stopped.
D. My vessel is healthy .

单项选择题Letter “H” means“（）”.

A. I have a pilot on board
B. I require a pilot
C. I have stopped
D. My vessel is healthy