— You may find the key to the maths problem on page 107. — Ah, it’s so simple. I wonder why I_________of that.
— What’s the matter with Peter? — He was seen crying when he was coming out of the office.He ________ by the manager.
— It _______ be Mr.Johnson who is in the office. — No, it _______ be him.I saw him off at the airport half an hour ago.
--Was the test hard? --The test was so hard that he ________ failed.
The computer is ________ to be one of the greatest inventions of the 20th century.
The seller would sell the shirt for ten yuan, but the customer ________ eight yuan.