The boy heard the engine, and he raised his head.

A moment later he heard the engine of a large truck.

I couldn't even hear the engine yet, so it would be impossible for them to see me.

It looked like a plane, but she couldn't hear the engine.

In a few seconds he heard the engine of the other van.

She could hear the humming engine behind the far wall.

I'm not sure we would have heard the engine of a 777.

A second later, the boys heard the engine of the blue convertible.

I could hear the engine idling against the still night air.

She heard the warm engine ticking over but nothing else.