Unit Six is ________ most difficult lesson, but it isn’t ________ most difficult one in this book.
—_____ you _____ your homework yet? —Yes, I _____ it ten minutes ago.
Now most families have only one child _____ our country’s one-child policy.
— Hello, this is Tom. Is Jack in? — Sorry, he to his uncle’s home. May I take a message?
—I’m worried about tomorrow’s math exam. — ______ . I’m sure you will make it.
Mrs. White _______dinner when her son came home.