I half thought he was going to rise from his chair, but he remained seated, although a remarkably well acted expression of astonishment rose on his face. 
I watched him closely to see what his reaction would be, and was inclined to think he was acting for our benefit.
He was standing as he heard the news and I was sure he would sit down.
The boys are playing a game
The man has a black shirt and a balloon.
The grand jury is incapable of seeing any discomfort a person may display.
A surfer is wearing a black shirt
The man is standing straight up.
I don't intend to pay for rent since she has all the money anyway.