He chuckled at the look she gave him, then turned more serious.

At the age of 15 his interest in music turned serious.

She sighed, then seemed to turn a little more serious.

This is where the happy story of tennis turns serious.

The smile on the President's face died and he turned serious.

He turned very serious long before they had finished telling him about it.

"My guess would be no." His face turned serious again.

But he turns oddly serious on the subject of going home again.

He looked at Honor, and his expression turned much more serious.

He was about to turn off the set when the announcer turned serious.