Modal Verbs of Deduction in the Past

We are not certain, but Andrew (a)   (break) his foot.

Look at those tracks! They are unmistakable. A bear (a)   (walk) here.

I refuse to believe it. Tim (a)   (get) the promotion. That would be absolutely ridiculous.

There's no doubt in my mind. Oliver Arkwright (a)   (paint) this masterpiece.

I am caught in two minds. On the one hand, the butler (a)   (steal) the money, but on the other hand, it could have been the cook.

I'm not entirely confident in my assertion, but I think you (a)   (see) a rare visual phenomena called a parhelion.

I knew it! William (a)   (hear) some good news. That is why he was grinning from ear-to-ear when I saw him in the office today.

He (a)   (buy) a Faberge egg. It must be a fake. All of the real ones are owned by a Russian billionnaire.

The audience (a)   (enjoy) the show. That is why they were shouting 'encore!' even after the second time the musicians returned!

Mark (a)   (feed) the dog this morning. The new can of dog food I bought hasn't been opened, and it was the only one in the cupboard.