1.The students have read about twenty English novels in the past three years. 2.I have my homework finished . 3.He has painted the front door green. 4.I've written an article.5.It has been raining these days. 6.I have come from Shanghai.（从上海来） 7.You've read very well. （强调一次刚完成的动作） 8.I have forgotten..（仍没想起来,可能已回忆起来了） 9.The book has been written in simple English..（表动态,已用英语写成） 10.Every time I have seen him, he's been reading.(强调两个动作同时进行） 11.He has gone .（强调动作和时间） 12.He won't come till the play has begun.（戏已开始） 13.After I have left school, I'll go to college.（强调毕业后,两个动作可能有间隔） 14.It's been a long time since I saw you last. 15.Where have you been?(去了哪） 16.He has lived in New York for eight years. 17.He has been called a thinker.18.You've heard what I said. (你听见我的话了） 19.I've seen him this morning.(还在上午的时间里)20. I've lost my pen. (笔还没找到）