Provide the appropriate tense form of the verbs in brackets.

Everyone _______ (sleep) by the time he reached home. The problem was that he had _______ (forgot) to take the keys. He didn't want to ring the doorbell and wake his family up. He could only _______ (imagine) how angry his parents would be for reaching home at this ungodly hour. He would be _______ (ground) for the rest of his life. But the concert he had gone to earlier, _______ (risk) his parents' wrath, was totally worth being grounded over.