5.they didn't often go to the cinema every Sunday last year.
->they didn't use to go to the cinema every Sunday last year 
6.my hair now is much longer than that in past.
->in the past mỹ hair used to be shorter 
7.i don't have time to collect stamps as when I was in primary school.
->i used to collect stamps when I was in primary school 
8.did you often go to the beach when you lived in Nha Trang?
->did you use to go to the beach when you lived in Nha Trang