1.Vinh is always forgetting his homework
2.do you mind helping mw put the chair away
3.i'd rather you didn't make any noise,i'm very tired
4.i have never used a better computer than this
5.it's ages since he has chatted with his classmates through the internet
6.the last time we saw her was when we left university
8.it's very important to keep the environment clean
9.Minh has collected stamps since 2000
