It is not always easy for the public to see _______ use a new invention can be of to human life.
31. He _____ have come here yesterday, but he didn’t.
He ought to win the first prize, _____ he?
I missed the last bus, so I _____ go home on foot.
I got up early that morning, but I _____ so because I had no work to do.
You must be a writer, _____?