重点讲解：
1. on earth (用于包含形容词最高级的名词短语后表示强调)世界上，人世间；
He wanted to be the fastest man on earth.
他想成为世界上跑得最快的人OWLd|OM|YmN18UCEK5a6。
2. because of 因为；由于；
Many families break up because of a lack of money.
许多家庭由于缺钱而破裂ORE9vWO|0M。
3. a collection of 一堆，一群(东西)；
Wye Lea is a collection of farm buildings that have been converted into an attractive complex.
“怀河草地”是一处由农舍改造而成的赏心悦目的建筑群^dZ@!rYGOsGW4,gN。
4. take effect 开始实施；生效；
The traffic laws don't take effect until the end of the year.
交通法要到年底才生效rT5|qJ5WlS。