6. There is a mistake in each of these sentences . Underline the mistake and then correct it. 1. It has started raining an hour ago. .............................................................................................................................. 2. I knew Hoa for some months. .............................................................................................................................. 3. We didn’t see Nga since Monday. ............................................................................................................................. 4. Lan was in the USA for 2 years. ............................................................................................................................. 5.I have gone to bed at 10 o’ clock last night . ............................................................................................................................... 6.They moved to London for 2003. ............................................................................................................................... 7. How long have you learn English ? .............................................................................................................................. 8. Peter was ill for a week. ...............................................................................................................................