… before/after …

结构︰

主要子句＋before／after＋子句

说明︰

此句型意为“…之前／之后”。<主要子句>的动作发生在<子句>动作之前或之后。before 引导的<子句>不可用否定式。

You must send some sample to the customer before you go abroad.
在你出国之前，应该先寄给客户一些样品。
After you think it over, please let me know by fax.
你仔细考虑过之后，请用传真相告。
What do you want to do after you have concluded this transaction?
这笔生意成交之后你想做什么？