I managed to get to bed before midnight for once. SUCCEEDED → For once ................................................ to bed before midnight.

I’m convinced that I was woken up by some kind of noise. MUST → It ................................................ some kind of noise that woke me.

The dream I had that night would later change the course of medical science. WAS → The dream I had that night ................................................ the course of medical science.

There is a rumour that the head of department will be retiring in the spring. BE → The head of department is ................................................ in the spring.

Alison would have come to the party unless something had happened to her. MUST → Something ................................................ to Alison or she would have come to the party.

I resolved the problem by talking to his mother. DID → What I ................................................ to talk to his mother.

Don’t ever say anything to John about the new scheme. CIRCUMSTANCES → Under ................................................ to John about the new scheme.

I only managed to recall the contents of my dream by going back to sleep. ONLY → It ................................................ back to sleep that I managed to remember the contents of my dream.

I regret not having written down that amazing dream I had. ONLY → If ................................................ that amazing dream I had.

I regret sending him that email. WISH → I ................................................ him that email.