They decided_________ to the mountain.
—________ English book is this?—Maybe it is Lucy's.
Yesterday something ________ happened. We didn't know what it was.
This coat ________ be Tom's. He doesn't like the color at all.
—Is Mr. Smith over there?—It ________ be him. He has gone to Beijing on business.
- was the car invented?--It was invented in 1983.