"A man could turn gray while waiting for you to answer a simple question."

The world started to turn gray in front of his eyes.

His face turned gray and he seemed ten years older.

His hair started turning gray by the time he was 14.

The water passed over his head, and the sky turned gray.

They turn gray and grow old while I am not watching.

An hour after that the sky began to turn gray.

Even in the poor light, they could see his skin starting to turn gray.

I am advanced in years and my hair has turned gray.

Since the light was already turning gray, they set out immediately.