There is a mistake in each of these sentences.Underline the mistake and then correct it
1.It has startedcraining an hour ago
................................................................
2.I knew Hoa for some months.
.........................................................
3.We didn't see Nga since Monday
..........................................................
4.Minh was in the USA for 2 years
............................................................
5.I have gone to bed ai 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.
.....................................................