Sometimes the boy is a bad-tempered child, but he ____ be quite lovely when he wishes.
We must set a limit __________ the expense of the trip.
He’s thinned down a lot since he ___________ a diet.
--- Did you find your book last night? --- Yes, I finally managed __________ the book I was looking for.
What are the differences between the American and British ____________of government?
Jack has made great achievements in his work, and the harder he works, the _________ he becomes.