单项选择题
A.hoist B.hoists C.hoisting D.hoisted
The main tasks for sailors on duty are, first of all,（）...
单项选择题The main tasks for sailors on duty are, first of all,（）the persons who come on board to do their business.
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
