And behind them jogged a middle-aged man with his own now solemn, now amiable, thoughts.

It doesn't have a solemn thought in its head, although the thoughts it does have are sometimes primal.

Within a darkness as total as that of the black hush, The Shadow dwelt in solemn thought.

That's a very solemn thought.

The lawyer gave the matter several seconds of solemn thought.

I don't believe you ever had a solemn thought in your head.

The black figure stood in solemn thought.

'You didn't favour me with that solemn thought in your letter to me on the Baghdad postcard.'

"Rice was not simply funnier than other clowns; he was different, mingling jokes, solemn thoughts, civic observations, and songs."

Then a solemn thought came to me.