1 he has had a cold for two days because he didn't wear enough warm clothes
-> thì HTHT
-> s + have / has + VPII
-> because + S + V + S + V
2 I stayed home because it rained.
-> thì QKĐ
-> because + S + V + S + V
3 They've decided to clean it up because it is full of rubbish
-> because + S + V + S + V
4 Because she works in that small town, she's lived there for three years.
-> thì HTHT
-> s + have / has + VPII
-> because + S + V + S + V
5 They think they should move there because the neighbourhood is nice and quiet
-> because + S + V + S + V
-> should + v nguyên mẫu