I. Fill the correct preposition "for" or "since".
1.They have only been there for few minutes
2. I have known them for many years.
3. My elder sister has been a college student for two years.
4. They have lived here since 2000
5.She has been away for three days.
6. It hasn't rained in the region for several months.
7. She has been here for many years and she loves it.
8. My brother has worked in this motor company since he left university.
9. She hasn't seen her closest friend for several years.
10. Jill has stayed in Ha Noi for six months.