vertical air movements
heavy rainstorms
horizontal air movements
any movement of moist air
第1题：
The first indications a mariner will have of the approach of a warm front will be ______.
A.large cumulonimbus (thunderclouds) building up
B.high cirrus clouds gradually changing to cirrostratus and then to altostratus
C.fog caused by the warm air passing over the cooler water
D.low dark clouds accompanied by intermittent rain
第2题：
Clouds with the prefix“nimbo”in their name ______．
A.are sheet or layer clouds
B.have undergone great vertical development
C.are middle or high altitude clouds
D.are rain clouds
第3题：
Passage Three
Many theories about the origin of the ocean have been proposed by scientists. The most widely accepted one is that the earth at some time in its very early history became hot enough to melt the materials from which it was formed. While in this molten state, lighter rock-forming materials (造岩材料) floated on the surface of the heavier ones. Then, between four and a half four billion (十亿) years ago, the molten earth cooled sufficiently to form. a crust of rock that was many miles thick.
Surrounding the earth was an unbroken canopy of clouds miles thick and made up mostly of water vapor. Rain falling toward the still-hot earth was heated to steam and rose to the clouds again. After many millions of years, as the earth continued to cool, its surface temperature fell below the boiling point of water. Rainwater could now remain on the earth, covering its whole surface except for the higher places on earth that had been formed from the lighter rock materials.
In 1970, scientists had pieced together evidence that the lighter rock materials had formed one huge continent by a vast ocean. Then, about 200 million years ago, the great continent began to break up, the pieces moving slowly apart.
The onrushing waters of the single huge ocean now entered and filled the spaces between the separating continents--and became the several oceans and seas we know today.
41. This passage mainly talks about ______.
A. the origin of the earth
B. the origin of the ocean
C. the history of the earth
D. the forming of the earth's crust
41．答案为B。根据第一段第一、二句，Many theories about the origin of the ocean have been proposed by scientists．The most widely accepted one is that...作出该项选择。
第4题：
Cumulonimbus clouds can produce ______.
A.dense fog and high humidity
B.gusty winds, thunder, rain or hail, and lighting
C.clear skies with the approach of a cold front
D.a rapid drop in barometric pressure followed by darkness
第5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
第6题：
The dense black cumulonimbus clouds surrounding the eye of a hurricane are called ______．
A.Spiral rainbands
B.Cloud walls
C.Funnel clouds
D.Cyclonic spirals
第7题：
Cumulus clouds that have undergone vertical development and have become cumulonimbus in form，indicate ______．
A.clearing weather
B.that a warm front has passed
C.probable thunderstorm activity
D.an approaching hurricane or typhoon
第8题：
Cumulonimbus clouds are most likely to accompany a(n) ______.
A.high pressure system
B.cold front
C.warm front
D.occluded front
第9题：
Altocumulus clouds are defined as______．
A.high clouds
B.middle clouds
C.low clouds
D.vertical development clouds
第10题：
High clouds, composed of small white flakes or scaly globular masses, and often banded together to form a mackerel sky, would be classified as ______.
A.cirrus
B.cirrocumulus
C.altostratus
D.Cumulonimbus