重点讲解：
1. go out
外出交际；外出娱乐；
eg. I'm going out tonight.
我今晚要出去玩。
eg. It will be a marvellous occasion and they should go out and enjoy it.
这是个好时机，他们应该出去痛快地玩一玩。
2. for free
义务地；无偿地；免费地；
eg. I wasn't expecting you to do it for free.
我并没有指望你白干。
eg. Why waste £50 when you could get it for free?
能够免费得到为什么还要浪费50英镑呢？
3. for example
例如；比如；
eg. Many great men have risen from poverty---Lincoln, for example.
许多伟人从贫困中崛起，例如林肯。
eg. There are many sources of air pollution; exhaust fumes, for example.
空气污染有许多来源，例如废气。