12、现在完成时;
Top 1: I really love that movie. I've seen it ten times;
我真的喜欢这部电影，我 已经看过十遍了。
Top 2: I've never met him before.;
我以前从来没有见过他。
Top 3: She's worked here for three years.;
她在这儿工作了三年。
20. A:I have been very busy the last few days.;
我最近几天比较忙。
B:I've been really worried about you. You should take care of yourself.;
我真为你担心。你得照顾 好自己。
21. A:I've finished my degree.Now I'm taking classes for fun;
（表示已经发生的事） 我修完学位了，现在我上 课纯粹是为了娱乐。
B:Oh, really? What classes are you taking;
哇，真的吗？你在上什么 课？