重点讲解：
1. day off
休假日；休息日；
eg. It was Mrs Dearden's day off, and Paul was on duty in her place.
那天迪尔登夫人休息，保罗替她当班。
eg. I work from Tuesday to Saturday, and Sunday and Monday are my days off.
我从星期二到星期六工作，星期日和星期一休息。
2. keep sb. from doing sth.
阻止（或防止、阻碍）某人做某事；
eg. Embarrassment has kept me from doing all sorts of things.
我总是害怕受窘，什么事都不敢去做。
eg. What can you do to keep it from happening again?
你怎样防止它再次发生？
3. If虚拟语气
文中用到的是，if从句表示与现在的事实相反的假设时，从句的谓语动词一般用过去时(be用were而不用was) ，主句谓语动词用should/would/could/might+动词原形
eg. If there were no air, people would die.
如果没有空气，人就会死亡。
eg. If I were in his shoes, I would not take such a risk either.
如果站在他的立场看问题，我也不会承担这个风险的。
eg. If he were alive now , he might have grown into a handsome young person.
要是他现在还活着的话，他会已长成一个英俊的小伙子了。