新闻中常说“大力整顿某行业、大力打击犯罪”等，英文中用crack down这个词组来表示“大力整顿”。我们先来看一个例子：
　　例句-1：For months, motorists had been speeding down Main Avenue. They caused a number of accidents including pedestrians being hit. That’s when more police officers were assigned to enforce the law. It’s worked. Since we crack down on speeding, there have been fewer problems.
　　几个月来，开车的人总是在主街大道上超速飞车，结果发生了好多起交通事故，还有行人被撞到。为此，警方在那里增加了警力，加强执法。这种大力管制很有效，管制开始以来，事故的数量减少了。
　　Crack down也可以表示“严格管制”，比如在下面的例子中，这位老板对员工管得就很严。
　　例句-2：I know the employee manual says that we only have an hour for lunch. But once in a while I have an errand to run and I get back a few minutes late to the office. My new boss is so strict about the rules. She’s taking notes on anyone who’s not at his desk on time. She’s really cracking down on us.
　　我知道员工守则上说我们的午饭时间只有一个小时，不过有时我有些杂事要办，也会晚个几分钟回办公室。我的新老板对这条规定特别较真儿。她会记下所有没按时回到办公桌前的员工名字。她管我们真是严格无比。
　　从上面例子可以看出，在crack down后面加人或物时，需要加介词on, to crack down on somebody or something意思就是大力整顿或者打击某事。另外，把crack 和down这两个词放在一起，就变成名词了crackdown, 意思一样，也是打击，镇压。
　　例句-3：The government began a crackdown on piracy.
　　政府开始大力打击盗版活动。