A.TornadoB.WaterspoutC.HurricaneD.CycloneWhen a tornado……

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

单项选择题When a hurricane passes into high latitudes over colder water and the source of heat is disrupted，the storm assumes the characteristics of（）.

A.a high pressure area
B.an extratropical cyclone
C.a tropical storm
D.an easterly wave

单项选择题What kind of pressure systems travel in easterly waves（）.

A.High pressure
B.Low pressure
C.Subsurface pressure
D.Terrastatic pressure

单项选择题What kind of conditions would you observe as the eye of a storm passes over your ship’s position（）.

A.Huge waves approaching from all directions，clearing skies，light winds，and an extremely low barometer
B.Flat calm seas，heavy rain，light winds，and an extremely low barometer
C.Flat calm seas，heavy rain，light winds，and high pressure
D.Huge waves approaching from all directions，clearing skies，light winds，and high pressure

单项选择题What is the first visible indication of the presence of a tropical cyclone or hurricane（）.

A.Stratocumulus clouds or strange birds
B.Rain and increasing winds
C.An exceptionally long swell
D.Dark clouds and the“bar”of the storm