It meant the man was chewing over a heavy problem.

The man chewed on that one for a moment or two.

Thing is, the old man had been chewing all his life.

The man in the smock was chewing his lower lip hard.

The older man had been chewing on a pencil.

The old man chewed his upper lip, worry written all over him.

The fat man chewed the end of his cigar.

The man couldn't talk and chew gum at the same time.

The young man chewed his lips, then spoke in a concerned tone.

The man had been chewing fennel seeds for his breath.