单项选择题
A.In B.On C.To D.For
（）using the derrick at once，the gooseneck is bent.A.Con...
单项选择题（）using the derrick at once，the gooseneck is bent.
A.Continue B.Start C.Commence D.Stop
（）this the Chief Officer agreed not to put any remarks....
单项选择题（）this the Chief Officer agreed not to put any remarks.
A.At B.By C.For D.Upon
（）there danger of explosion?A.IsB.HasC.IfD.Do
单项选择题（）there danger of explosion?
A.Is B.Has C.If D.Do
