He asked a lot of questions, none of ______ was easy to answer.
You _____ practise the drums while the baby is sleeping.
The police still haven’t found her, but they’re doing all they _____.
The World Wide Web is sometimes jokingly called the World Wide Wait because it _________be very slow.
—The woman biologist stayed in Africa studying wild animals for 13 years before she returned. — Oh, dear! She _________ a lot of difficulties!
—Lucy doesn’t mind lending you her dictionary. —She _________. I’ve already borrowed one.