Earthquakes can cause great loss of life by destroying structures such as buildings, bridges, and dams, and they can also produce dangerous landslide (山崩). Another destructive effective effect of earthquakes is the genetation (振荡) ,usually by sub-sea tremor(振动),or so-called tidal waves. Their towering walls of water have struck populated coastlines so violently that entire towns have been destroyed.
Three general classes of earthquakes are now recognized: tectonic (地壳构造的), volcanic, and artificially produced, the tectonic variety is by far the most harmful, and such quakes cause particular difficulties for scientists trying to develop ways to predict them. Earthquakes of volcanic origin are seldom very large or destructive. Humans can cause earthquakes through a variety of activities.
Historical written accounts of earthquakes before the middle of the 18th century are generally rare and not reliable. The earthquake in 1556 in Shanxi Province of China, which killed
The Internet use appears to cause a loss in psychological (36) , (37) a research (38) the Carnegie Mellon University.
(39) people who spent just (40) hours a week on the Internet experienced more depression(沮丧) and loneliness (41) those who spend less time on the Net, the (42) study showed. And it wasn’t (43) people who were already feeling bad spent more time on the Internet, but that using the Net actually appeared to cause the bad feelings.
Researchers are (44) at the results, (45) were completely (46) to their views. They expected that the Net would prove socially (47) than television, since the Net allows users to choose their information and to communicate with others.
The fact (48) the Internet use reduces time available for family and friends may (49) for the drop in well-being. Faceless, bodiless communication may be le
A. that
B. which
C. who
D. they
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