4.B:Well,if you had studied harder,you wouldn't have failed
5.B:If I were you,I would go to the dentist.
6.B:If I hadn't left the door open,the puppy wouldn't have escaped.
7.B:If I had not been late,we wouldn't have missed the bus.
8.B:Where would you go,if you could travel anywhere in the world?
9.B:If I were you,I would go to America.
9.B:Well,if I were you,I would report it to the police.
10.B: Well,if you had been careful,you wouldn't have cut yourself.