重点讲解：
1. serve as 担任；任职；
She was elected to serve as secretary of the local party.
她当选为地方党组织的书记。
2. be familiar with 熟悉；熟知；
Tom is quite familiar with the author.
汤姆很熟悉那位作家。
3. be set to do sth. 做好准备的；可能的；
The price of cigarettes is set to rise again.
香烟又要涨价。
4. stem from 起源于；来自；由…造成；
All my problems stem from drink.
我所有的问题都源于酗酒。