单项选择题
A.aboard B.board C.go ahead D.go forward
（）scale charts are used for harbors.A.SmallB.LargeC.Lor...
单项选择题（）scale charts are used for harbors.
A.Small B.Large C.Loran D.Route
（）is the maximum speed of your ship?A.HowB.WhichC.How a...
单项选择题（）is the maximum speed of your ship?
A.How B.Which C.How about D.What
The fog is too thick. Don’t（）the radar.A.switch onB.swi...
单项选择题The fog is too thick. Don’t（）the radar.
A.switch on B.switch off C.close D.open
