根据上下文补全对话。

A: Rob, you look upset!

B: I'm worried about Mr. Smith.

A: Where is he?

B: Maybe he is hurt. Look at his desk.

A: Oh, there are papers everywhere. There is some bread his desk.

B: And there is some coffee on the desk, too.

A: See? Something bad might have happened.

B: Oh, Betty. I just touched the coffee. It is still hot.

A: He must be nearby

B: Oh, there some coffee on my hand. I need a tissue(纸巾).

A: But the box is empty.

B: You can find some in the next-door office.

A: Oh, the door is locked. But I can hear something inside.

B: Let's with the key and have a look!

A: Oh, Mr. Smith is here. He is sitting on the chair and thinking about something.