题目内容
all of them are destructive. The intensity (强度) of an earthquake is measured on the Richter Scale, which goes from zero upward. The highest magnitude recorded to date is 8.9Major damage generally occurs
from quakes ranging upwards from 6.0.
The actual cause of earthquake itself is the breaking of rocks at or below the breaking of rocks or
below the earth's surface. This is produced by pressure which scientists believe may be due to a number
of reasons, two of which are the changed of the earth's crust (外壳) and continental drift(漂流).
In order to minimize the damage and to decrease some of the pain resulting from earthquakes,
scientists are working on ways to improve accurate prediction. Two kinds of the instruments now in use
to achieve this goal are seismograph(地震仪) and tilt (倾斜) meter. The former records any shaking of
the earth. Seismologists ca accurately record the exact time, location and size of an earthquake. The latter, as the name suggests, is used to record any changes in the tilt of the land.
B. Major damage usually happens when the intensity of an earthquake is below 6.0
C. Scientists usually use seismographs and tilt meters to predict earthquakes now.
D. Continental drift may cause an earthquake.
A.Scientists are working hard to predict the earthquakes.
B.The reason why earthquakes happen.
C.Introduce the earthquake and its prediction.
B. A report
C. A science magazine.
D. A history book.
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