He ________ goes to the National Library of China, once a month at most.
We ________ have hurried all the way to the airport — the flight was called off because of the foggy weather.
—Mike, I can't find my watch anywhere.—You ________ it while working out.
—Where did you get this book?—I picked it up from a secondhand bookshop if you ________ know.
Jack is an outgoing child, usually kind and helpful, but he ________ lose temper sometimes.
________ a little earlier, you could have got a copy of his latest book.