When the cat's away, the mice will play.

　　山中无老虎，猴子称霸王。

　　When the cat's away, the mice will play.直译过来就是：“猫儿不在家，耗子就会出来活动”，这个短语的正确意思是：“山中无老虎，猴子称霸王”。因此，当美国人说"When the cat's away, the mice will play."时，他/她要表达的意思就是:"The subordinates will do as they like when the superior is away."、"The weak will become active without the strong."。

　　情景对白：

　　Shirley: Do you know the boss's assistant has criticized a few colleagues today just for some trivial things? We should take care.

　　雪莉：你知道吗？老板助理今天因为一些小事批评了几个同事。我们最好当心点。

　　Jane: Yeah. The boss is away at the moment. When the cat's away, the mice will play.

　　简：是啊，现在老板不在，山中无老虎，猴子称霸王。

　　搭配句积累：

　　①Now the project should be in the charge of an assistant for the boss is on a business trip.

　　老板出差了，现在这个项目竟然由一个助理负责。

　　②The staff become too casual without the boss there.

　　老板不在，员工们越来越散漫了。

　　③She turned down our application for more technical personnel without asking the boss.

　　她没问过老板，就拒绝了我们要更多多技术人员的申请。

　　④A little secretry should dare yell at us.

　　一个小小的秘书居然敢冲我们大吼。