1. The pen is being used to write.
2. They spends/spent/have spent all their time on the work.(取决于什么时态,习惯就用第三人称,过去式,或者一般完成式都可以）
3. I haven't visited/seen my aunt for a long time, so I want to visit her this winter holidy.
4. It seems that he didn't catch the train.
5. Even though this book is expensive, I bought it.
6. We tried in many ways and solved this problem in the end.
7. It's necessary for students to have enough sleep.
t's necessary for students to sleep for a enough time.
8. Since Tony moved to Shanghai, he hasn't called me.