1.We haven't any matches so we can't light a fire
If we had had some matches , we could light a fire
2.We didn't listen carefully,we made this mistake
if we had  listen carefully , we wouldn't  have made this mistake
3.We got a lift,so we reached the station in time
if we hadn't got a lift , we would have reached the station in time
4.You washed it in boiling water,that's why it shrank\
if we had  washed it in boiling water,it would shrank