重点讲解：
1. fall on
落到；落在……上面；
eg. A mass of snow and rock break away and fall on the climber.
一堆积雪和岩石突然崩落到登山者的身上。
eg. Everybody took cover when the bombs began to fall on the town.
轰炸时，镇上的每个人都藏了起来。
2. a chunk of/chunks of
大量；大块；大部分；
eg. The company owns a chunk of farmland near Gatwick Airport.
该公司拥有盖特威克机场周边的大片农田。
eg. They had to be careful of floating chunks of ice.
他们必须当心大块浮冰。
3. prompt sb. to do sth.
促使；推动；引发某人做某事；
eg. Japan's recession has prompted consumers to cut back on buying cars...
日本经济的不景气使得消费者在购买车辆上减少了开支。
eg. His curiosity prompted him to ask questions .
他的好奇心激起他问许多问题。