今天，我们来看一下有关于let的习语。
　　let alone, means not to mention; much less.是指更不用提；更别说的意思。例如：
　　Their ancestors had been dirt poor and never saw royalty, let alone hung around with them?
　　“他们的祖先穷得要命，从来没有见过王族成员，更不用说和他们在一起了”。
　　let go, means to cease to employ; dismiss.是指不再雇用；解雇的意思。例如：
　　had to let 20 workers go.
　　必须解雇二十名工人。
　　let off on, means to cause to diminish, as in pressure; ease up on.是指降低，如压力；缓和的意思。例如：
　　Let off on the gas so that we do not exceed the speed limit.
　　减小油门以防止超过限速。
　　let (one's) hair down, means to drop one's reserve or inhibitions.是指消除某人的拘谨或压抑的意思。

来源 http://www.translator.com.cn/content/garden/garden.asp?kind=AI