19. Everyone … very frightened if someone … a gun at him.
A) were/would point B) will be/pointed C) will be/will pointed D) would be/pointed
20. Has anyone left a letter for me?
Do you know if … a letter for me?
A) anyone left B) anyone had left C) has anyone left D) anyone has left
Earthquakes are the most lethal of all natural disasters. What causes them? Geologists explain them in terms of a theory known as plate tectonics. Continents are floating apart from each other this is referred to as the continental drift. About sixty mile below the surface of the sea, there is a semi molten bed of rock over which plates, or slabs, carry continents and sea floors at a rate of several inches a year. As the plates separate from each other, a few sea floor is formed by the molten matter that was formerly beneath. Volcanic islands and large mountain ranges are created by this type of movement. The collision of plates causes geological instability such as that in California called the San Andreas Fault, located between the Pacific and North American plates. The plates there are constantly pushing and pulling adjacent plates, thereby creating constant tremors and a potential for earthquakes in the area. Geologists would like to be able to predict earthquakes accurately. Using laser beams, seismographs, gravity-measuring devices, and radio telescopes, they are presently studying the San Andreas Fault to determine the rate of strain and the amount of ground slippage.
21. Continental drift is the concept that ...
A) new continents are developing beneath the sea. B) continents are drawing nearer to each other.
C) continents are 60 miles apart from each other. D) continents are separating.
22. Geologists are using modern technology to ...
A) enhance their reputations. B) measure the accuracy of earthquakes.
C) help predict earthquakes. D) control ground slippage.
23. It is clear from the text that an earthquake …
A) occurred sixty kilometres below the ocean B) isn`t important to separate continents
C) is caused by movements of tectonic plates D) can`t be stopped by technologies
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