现在完成时的句子怎么翻译

1.你去过上海吗？ 不，从没有
2.你做完作业了吗？ 不，还没有
3.他还没有看完这本书
4.火车还没有开
5.你在北京住了多上时间了？ 七年
6.现在凯特在哪？ 他在伦敦
7.我找不到手表了，我想它已经丢了
8.你以前见过他吗？ 是的

　　Have you been to Shanghai? No,never.
Have you finished (doing) your homework? Not yet.
He hasn't finished reading the book.
The train hasn't started.
How long have you been living in Beijing? 7 years.
Where's Kate now? She has been in London.
I can't find my watch. I think it has been lost.
Have you ever seen him? Yes.

发生在过去但状态或其结果或影响持续到现在的动词时态，构成：have/has+done/been doing简单翻译例句如上，大多数翻译都是....加已经...

I have finished my work.我已经完成了工作
I have never seen a tiger.我从未见过老虎