单选题Earthquake is a shaking of the ground caused by the sudden breaking and the shifting of large sections of the earth's rocky outer shell. Earthquakes are among the most powerful events on earth, and their results can be terrifying. A severe earthquake may release energy 10,000 times as great as that of the first atomic bomb. Rock movements during an earthquake can make rivers change their courses. Earthquakes can trigger landslides that cause great damage and loss of life. Large earthquakes beneath the ocean can create a series of huge, destructive waves called tsunamis that flood coasts for many miles. Earthquakes almost never kill people directly. Instead, many deaths and injuries in earthquakes result from falling objects and the collapse of buildings, bridges, and other structures. Fire resulting from broken gas or power lines is another major danger during a quake. Spills of hazardous chemicals are also a concern during an earthquake. (77) The force of an earthquake depends on how much rock breaks and how far it shifts. Powerful earthquakes can shake firm ground violently for great distances. During minor earthquakes, the vibration may be no greater than the vibration caused by a passing truck. On average, a powerful earthquake occurs less than once every two years. At least 40 moderate earthquakes cause damage somewhere in the world each year. About 40,000 to 50,000 small earthquakes--large enough to be felt but not damaging-----occur annually.
单选题
The passage is mainly about______ A. earthquakes and their effects B. the way of earthquakes taking place C. the classification of earthquakes D. the damaging results of earthquakes
单选题
When an earthquake occurs, ______ A. people are killed and injured B. rocks are breaking and shifting C. destructive waves flood the coasts for miles D. large sections of the earth's rocky outer shell suddenly break and shift
【正确答案】
D
【答案解析】由开头第一句可知，地震产生的原因是由于大面积的地壳岩层的突然破裂和移动所致。故选D。
单选题
The earthquakes which may not be so destructive are______ A. those beneath the ocean B. those do not kill people directly C. moderate earthquakes D. minor earthquakes
单选题
The intensity of an earthquake depends on ______ A. the movements of the earth's shell B. where it takes place C. the injuries it causes D. how far away it is from a city
单选题
It is implied that ______ A. powerful earthquakes usually occur after minor ones B. modem facilities add to the danger of an earthquake C. passing trucks are as dangerous as minor earthquakes D. there is a powerful earthquake occurring every two years