A、They were the most terrible disaster on earth. B、They were warning signs of some big events. C、They were turnovers of the big

The danger from earthquakes is very real—they are probably the most terrible natural disaster on earth. [12]It was thought in the past that earthquakes were punishment from an angry god. Only recently have scientists begun to understand why earthquakes happen.
    Scientists could not understand earthquakes until they understood more about the earth’s surface. [13] According to their findings, there are twelve huge plates that make up the surface of the earth. The oceans and lands rest on these plates which fit together like huge pieces of a jigsaw puzzle.
    The plates do not fit perfectly, however—they are always moving. Some plates are slowly moving apart and others are moving together. The plates that begin in the middle of the Atlantic Ocean are moving apart and the plates that meet in the Pacific Ocean are pushing together. [14]In fact, the Atlantic Ocean is slowly growing larger and the Pacific Ocean is getting smaller. Earthquakes occur when two plates that are pushing against each other slide violently past each other. A large amount of energy is released, and the land on top of the plates shakes, causing cracks to appear in the ground and waves to form in the ocean. Terrible destruction can occur; buildings can be destroyed, and fires started.
    Because most earthquakes occur at places where two plates push against each other, these places, called faults, are very dangerous. [15]The famous San Andreas Fault is the meeting point of the Pacific and the North American Plates. The San Francisco earthquake of 1906, which almost completely destroyed the city, occurred because San Francisco is very close to the San Andreas Fault.
12. What did people think of earthquakes in the past?
13. According to the speaker, what do the findings from the scientists tell us?
14. What happens to the Atlantic Ocean according to the passage?
15. What do we learn about the famous San Andreas Fault?