roll down
to move downward, rotating, as a wheel or a ball, or to move downward on wheels. I pushed the wagon up the driveway, and it rolled down again. Don't place the cart at the top of the hill. It will roll down.
roll down something
to move downward, along something, rotating, as a wheel or a ball, or moving downward on wheels. The ball rolled down the hall to the end. The cart went rolling down the hill all by itself.
roll something down
1. to move something down, making it rotate like a wheel or a ball, or moving it on wheels. Don't carry the ball down; roll it down! I rolled down the ball as you asked.
2. to crank down something, such as a car window. Please roll the window down and get some air in this car. Please roll down the car window.
roll something down something
to cause something to move down along something, rotating it like a wheel or a ball. Claire rolled the bowling ball down the alley for a strike. Roll the barrel down the ramp carefully. It is heavy.