14. People will keep the environment clean They will throw rubbish mto the right bin

->If people throw rubbish into the right bin , they will keep the environment clean

15. Robert gets a bad cough because he smokes cigarettes.

-> If Robert didn't smoke cigarettes , he would not get a bad cough

16. He is late every day, that's why he will lose his job.

->If he weren't late every day, he would not lose his job

17. The party might go on all night. If it does, no one will want to do any work tomorrow.

-> if the party doesn't go on all night ,  no one will want to do any work tomorrow.

18. I don't know the answer, so I can't tell you.

-> If I knew the answer , I could tell you.