重点讲解：
1. open up
开辟；打通；
eg. As rescue workers opened up roads today, it became apparent that some small towns were totally devastated.
今天救援人员打通了道路后，人们发现一些小镇显然已被彻底摧毁。
eg. The sales manager wants to open up new markets in the Far East.
销售经理想在远东开辟新市场。
2. have an impact on sth.
对……产生影响；作用；
eg. Technology has had an irreversible impact on society.
技术已对社会产生不可逆转的影响。
eg. There's no question that the ads had a real impact on the public.
毫无疑问，这些广告对公众确实产生了影响。
3. from time to time
不时地；间或；偶尔；
eg. Her daughters visited him from time to time when he was ill.
他生病的时候她的女儿们时常去探望他。
eg. From time to time,she gave him an encouraging nod.
她不时对他点头鼓励。