rising air currents produced by the warm islands
warm air from the sea rising over higher land areas
cool land air mixing with warm sea air
descending air over the islands
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：
__________
A. clouds B. weather C. pictures D. trees
第4题：
Many of the lights on this coast are placed so high as to be frequently obscured by______．
A.power
B.tower
C.cover
D.low clouds
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：
In many areas "atoll" clouds (clouds of vertical development) are produced over small islands. These are the result of ______.
A.rising air currents produced by the warm islands
B.warm air from the sea rising over higher land areas
C.cool land air mixing with warm sea air
D.descending air over the islands
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：
1． There are many clouds coming，it_________ rain soon．
A．will be
B．is going to
C．looks like
D．likes
第9题：
Altocumulus clouds are defined as______．
A.high clouds
B.middle clouds
C.low clouds
D.vertical development clouds
第10题：