eg. The duty of the local authority is to look after the interests of the local people.
地方当局的职责是照管当地人民的利益。

eg. My job is to look after these patients.
我的工作就是照顾好这些病人。

2. “start the ball rolling”意思是“正式开始”。

eg. He started the ball rolling at the party by telling a new joke.
在聚会上，他说了个新笑话使大家开始谈起来。

eg. It just needs such a thing to start the ball rolling, and it will open the way for many changes.
只需要有这样一件事情来启动，就会打开带来许多改变的道路。