I
1. was
2. had arrived
3. wouldn't have loosen
4. had pressed
5. had fed
II
1. If the road hadn't been icy, the accident would't have happened
2. If he hadn't followed this treatment, the patient would have died.
3.If he hadn't been late every day, he wouldn't have lost his job.
4. If Peter didn't eat so many chips, he wouldn't be fat.
5. If Robert had not started smoking cigarettes, he would not have got a bad cough.