Frank is not going to the graduation ceremony because he broke his leg snowboarding last week.

Frank would be going to the graduation ceremony if he had not broken his leg snowboarding last week.

Frank would go to the graduation ceremony if he had not broken his leg snowboarding last week.

Frank would not be going to the graduation ceremony if he had broken his leg snowboarding last week.

Frank would have been going to the graduation ceremony if he had not broken his leg snowboarding last week.