重点讲解：
1. for instance 例如；譬如；
You cannot rely on her, for instance, she arrived an hour late for an important meeting yesterday.
她这人靠不住，例如昨天一个重要会议，她竟迟到了一个小时。
2. step up 增加(数量等)；提高(速度、强度等)；
Government reforms to gas pricing models for exploration and production companies have encouraged them to step up their activities.
政府对勘探及生产企业天然气定价模式的改革，鼓励了这些企业加紧勘探及生产活动。
3 a series of 一连串；一系列；连续；接连；
The students have put forward a series of questions.
学生们提出了一系列问题。
4. search for 搜寻；搜索；搜查；寻求；
The police cordoned off the railway station to search for the escaped prisoner.
警察在车站戒严，搜捕逃犯。