单项选择题
A.received B.receives C.receiving D.receive
Where are （）goods carried on board?A.dangerB.dangerousC...
单项选择题Where are （）goods carried on board?
A.danger B.dangerous C.A+B D.A or B
（）social instruction on cargo securing.A.HasB.HadC.Have...
单项选择题（）social instruction on cargo securing.
A.Has B.Had C.Have D.Having
Go （）this ladder and walk aft.A.downB.toC.upD.in
单项选择题Go （）this ladder and walk aft.
A.down B.to C.up D.in
