重点讲解：
1. be sure to do sth.
（事情的发生）一定，必然；
eg. Our product is sure to win out over those of our competitors.
我们的产品肯定会优于我们对手的产品。
eg. You're sure to be blown up for coming late to work.
你一定会因为上班迟到被责骂。
2. change one's mind
（使）改变主意；（使）改变决定；
eg. It would be impossible to change his mind.
要让他改变想法是不可能的事情。
eg. She's very young. She might change her mind about what she wants to do.
她很年轻，对于自己想要做的事情也许会改变主意。
3. in search of
寻找；寻求；
eg. Migratory workers migrate to cities in search of work.
流动工人移往城市找寻工作。
eg. The scientists are in search of a new element.
科学家们正在寻找一种新元素。
4. hurry to do sth.
赶紧（做）；急忙（做）；匆忙（做）；
eg. Mrs Hardie hurried to make up for her tactlessness by asking her guest about his holiday.
哈迪夫人赶紧问客人假期过得怎么样，替自己的言不得体打圆场。
eg. They started a few minutes ago, and we must hurry to catch up.
他们几分钟前已出发，我们必须赶紧追上。
5. on duty
上班；值班；
eg. There were 2,250 policemen on duty in and around the stadium.
在体育场内及周边有 2，250 名警察在值勤。
eg. Extra staff had been put on duty.
编外人员已经就职。