Correct the mistake in the sentences

Correct the mistake in the sentences
1.They didn't let me to go
2.She failed her examination like her friend did
3.I buy a new house if I have enough money
4.He has learnt Chinese enough to study in China
5.Nobody have used to this house for a long time 
6.His garden isn't as large than mine
7.We haven't talked to your sister a long time
8.There are much than eighty stores in the mall