A.A backing windB.A veering windC.Sustained gale force ……

单项选择题Which condition indicates that you are in a hurricane’s dangerous semicircle in the Northern hemisphere（）.

A.A backing wind
B.A veering wind
C.A norther
D.A strong，gusty wind

单项选择题When your vessel is on or near the path of an approaching tropical storm the（）.

A.wind direction remains steady
B.wind speed increases
C.barometer falls
D.All of the above

单项选择题When experiencing heavy winds，you should reef sails to（）.

A.bring the sails parallel to the wind
B.reduce sail area exposed to the wind
C.allow the sails to catch more wind
D.remove all tension on the main and jib sheets

单项选择题When a tornado moves over the water from land it is called a（）.

A.Tornado
B.Waterspout
C.Hurricane
D.Cyclone

单项选择题Wen a hurricane passes over colder water or land and loses its tropical characteristics，the storm becomes a（n）（）.

A.High pressure area
B.Extratropical low-pressure system
C.Tropical storm
D.Easterly wave