Her face was quite white, and she seemed to be lost in thought.

For a long moment he seemed to be lost in thought.

She was lost deep in thought for a moment and then looked up.

He too had been lost in thought, and now looked up.

He should have looked like a man deep in thought.

At best he was in deep thought and might not turn around.

For a couple of minutes Ha$hi seemed lost in thought.

He seemed lost in thought for a full two minutes.

My mind was too full for sleep and I sat by the fire, lost in thought.

He knew she might stand lost in thought for ten minutes or more.