"The tone of the House committee has changed this year."

But the tone has changed - she is trying too hard.

But, before she could work out why, his tone had changed again.

But, he found, the tone of the literature changed in the 1950's.

But sometime in the early 1980's the tone changed again.

His tone changed as he spoke away from the phone.

Well, they never showed me, and their tone changed after that.

The tone had changed, there was an edge to his voice.

Then when he turned to us, his tone of voice suddenly changed.

His tone changed as he thought about what he'd just said.