It had not been my intention to do any heavy thinking.

I'll turn the heavy thinking on that over to you.

It's too early in the morning to do such heavy thinking.

I have some heavy thinking to do so I'm going to blow.

Well, I got it off the boat and did a bit of heavy thinking.

I have to get by myself for a bit and do some heavy thinking.

I did some heavy thinking after school on Tuesday.

Norman dropped into his kitchen chair and did a bit of heavy thinking.

Or maybe she'd just checked out to do some heavy thinking.

Except when he was into heavy thinking, he could not stay still.