The river water is flowing quietly.

It's dangerous to cross the river by boat because the rapids are flowing fast.

Mr. Kawase is my best friend.

This road is dangerous, so please be careful.

Please avoid this road because it's dangerous.

We rowed a boat on the lake.

He went to school by crossing the bridge.

His running speed is really fast.

His running speed is astonishing.

His running speed is astonishing.