Most earthquakes occur within the upper
15 miles of the earth’s surface. But earthquakes can and do occur at all depths
to about 460 miles. Their number decreases as the depth increases. At about 460
miles one earthquake occurs only every few years. Near the surface earthquakes
may run as high as 100 in a month, but the yearly average does not vary much. In
comparison with the total number of earthquakes each year, the number of
disastrous earthquakes is very small. The extent of the disaster in an earthquake depends on many factors. If you carefully build a toy house with an erect set, it will still stand no matter how much you shake the table. But if you build a toy house with a pack of cards, a slight shake of the table will make it fall. An earthquake in Agadir, Morocco, was not strong enough to be recorded on distant instruments, but it complete A. (A) The number of earthquakes is closely related to depth. B. (B) Roughly the same number of earthquakes occur each year. C. (C) Earthquakes are impossible at depths over 460 miles. D. (D) Earthquakes are most likely to occur near the surfaces. [单项选择]Most earthquakes occur within the upper 15 miles of the earth’s surface. But earthquakes can and do occur at all depths to about 460 miles. Their number decreases as the depth increases. At about 460 miles one earthquake occurs only every few years. Near the surface earthquakes may run as high as 100 in a month, but the yearly average does not vary much. In comparison with the total number of earthquakes each year, the number of disastrous earthquakes is very small.
The extent of the disaster in an earthquake depends on many factors. If you carefully build a toy house with an Erector set, it will still stand no matter how much you shake the table. But if you build a toy house with a pack of cards, a slight shake of the table will make it fall. An earthquake in Agadir, Morocco, was not strong enough to be recorded on distant instruments, but completely destroyed the city. Many stronger earthquakes have done comparatively little damage. If a building is well constructed and built A. The number of earthquakes is closely related to depth. B. Roughly the same number of earthquakes occur each year. C. Earthquakes are impossible at depths over 460 miles. D. Earthquakes are most likely to occur near the surfaces. 我来回答: 提交
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