Tom hasn’t come to work since last Friday.       he have had an accident?

The boy is afraid of darkness, so he _____ out at night.

Li Lei isn’t ____ Liu Ming. 

Curious about the world around him, my son__   __ask me endless questions when he was young．

 ---The book _____ be Tom’s.---No, it _____ be his. There’s a name on the book. It’s Jim’s.