An earthquake is a shaking of the ground____(cause) by the sudden breaking and shifting of large sections of Earth's rocky outer shell. Earthquakes are among the most____(power) events on earth, and their results can be terrifying. Rock movements during an earthquake can make rivers____(change) their course. Earthquakes can cause great damage and loss of____(live). Large earthquakes beneath the ocean can create a series____huge and destructive waves called tsunamis____flood coasts for many miles. Earthquakes almost never kill people____(direct). Instead, many deaths and injuries in earthquakes result from ____(fall) objects and the collapse（倒塌）of buildings, bridges, and other structures. Fire caused from broken gas or power lines is another major danger during____quake. Spills（溢出）of ____(harm) chemicals are also a concern during an earthquake.