Please tell the duty AB to lower the （）.

单项选择题The captain has （）ashore.

A.go
B.going
C.gone
D.went

单项选择题When a ship is in port, （）must keep a gangway watch.

A.officers
B.crew members
C.sailors
D.motorman

单项选择题When a ship is in port, the sailor on duty （）a gangway watch.

A.has
B.keeps
C.looks
D.takes

单项选择题Hang national flag upside down should be strictly （）.

A.prohibit
B.prohibited
C.prohibiting
D.prohibits

单项选择题When you hoist national flag, you should hoist it（）.

A.quickly
B.rapidly
C.slowly
D.speedily