They walked along in silence, each man occupied with his own thoughts.

I never did catch his name, and on the drive we were both too occupied with our thoughts to talk.

He was occupied with his own thoughts and responsibilities that morning.

For some time they did not speak, each occupied with his own thoughts.

The fellows occupied themselves for quite a while with their own thoughts.

Each was occupied with her own thoughts for a time.

Or perhaps each of us was occupied with his own thoughts.

They did not speak much, each no doubt occupied with his own thoughts.

For some time they stood in silence, each occupied with his own thoughts.

They talked little, each occupied with his own thoughts about the case.