重点讲解：
1. close off 隔绝；封锁；
例句：Police closed off about 12 blocks of a major San Francisco thoroughfare for today's march.
由于今天的示威游行，警方封锁了旧金山一条主干道上大约12个街区。
2. so as to do sth. （用于引出原因）为了；以便；
例句：You should exercise more so as to keep energetic.
你应当多锻炼以保持精力充沛。
3. cut down 砍倒（树木）；
例句：A vandal with a chainsaw cut down a tree.
一个故意破坏公物的人用链锯伐倒了一棵树。
4. suffer from （因疾病或处于其他不利境地而）受苦，受难，受折磨；
例句：Many kids suffer from acne and angst.
许多年轻人都会受到青春痘和焦虑的困扰。
5. make up 组成；构成；
例句：Women officers make up 13 per cent of the police force.
女警占警力的13%。
6. account for （数量或比例上）占；
例句：Drug costs account for a higher proportion of the total medical costs.
药品费用占医疗总费用比例较高。
7. in an effort to do sth. 为了做某事；努力做某事；
例句：She has been studying very hard in an effort to catch up with her classmates.
她学得非常努力，以便赶上她的同学。
8. break up （使）分裂；（被）拆分；（使）破碎；散（会）；（使）解散；
例句：Police tried to break up the gang.
警察试图瓦解黑帮。
