We were about to leave, when an unexpected and unpleasant sound struck our ears.

The raider's head appeared above the wall, looking for the source of the unexpected sound.

It was a cheerful, unexpected sound, and made them all smile.

Both boys hastily turned round at the unexpected sound of a voice behind them.

"There's another thing," said John suddenly, and the unexpected sound of his voice made me start guiltily.

Then, to the detective's startled ears came an unexpected sound.

Startled by the unexpected sound booming out of the darkness.

She made a small unexpected sound and went rigid for just a second, before becoming extremely soft in his arms.

He decided to knock again, when an unexpected sound broke the silence that lay within.