A METHOD OF TOWING VESSELS THROUGH POLAR ICE BY MEANS OF ICEBREAKING TUGS WITH A SPECIAL STERN NOTCH SUITED TO RECEIVE AND HOLD THE BOW OF THE VESSEL TO BE TOWED defines（）.

单项选择题A MARK OR POSITION AT WHICH A VESSEL IS REQUIRED TO REPORT TO ESTABLISH ITS POSITION defines（）.

A.VTS point
B.Way point
C.Reference point
D.Establishment point

单项选择题（）will the discharging operations take?

A.How long
B.How length
C.How many times
D.How many shift

单项选择题（）will reduce the visibility.

A.dust
B.sea water
C.land sand
D.wind

单项选择题（）view of the fact，I wish to submit this report.

A.In
B.On
C.To
D.For

单项选择题（）using the derrick at once，the gooseneck is bent.

A.Continue
B.Start
C.Commence
D.Stop