A．Because the waves coming from the center of a quake can spread to these places.
B．Because there are the thickness of rocks making up the earth’s crust.
C．Because some parts of the earth are more likely to have quakes than others.
D．Because mountainous areas are easy to have earthquakes.

A．They eat huge mounts of food.
B．They usually eat twice a day.
C．They usually eat to their hearts’ content.
D．They eat much less than people assume.