I have this theory that, to us the world is a flat thing we stand on, but to birds it is a cliff they cling to, a huge ball and they cling to the side and then fall off and fly and glide.

我有一种想法，就是对我们来说世界是一个我们所站立的平坦的东西，而对鸟来说是一个它们所依靠的峭壁，一个巨大的球，它们依靠在边上，然后离开、飞翔、滑行。

youdao

Start as shown with the arms extended, back flat, legs fully extended and the balls of the feet on the Swiss ball.

开始动作如图所示：两臂伸直，背部保持平直，两腿充分蹬伸，脚掌置于健身球的球体之上。

youdao

Lean on the ball as shown, keep the back flat or maintain its natural curve, with the legs straight.

身体俯卧于球体之上，动作如图所示。背部保持正直或保持自然弯曲状态，腿部伸直。

youdao

A ball of clay is placed on a flat wheel device that turns quickly.

VOA: special.2009.09.09

Playing a wider game, Ireland attempted to concentrate on working the outside channels with the dangerous, quick, flat ball rather than grunting and boring their way through the packed close-in defenders.

BBC: Ireland coach Eddie O'Sullivan

They're flat and the ball doesn't get much above stump high.

BBC: Flintoff keen to join IPL in 2009

Owen's goal, on 17 minutes, came after Riise lobbed the ball over a flat-footed Joos Valgaeren.

BBC: SPORT | Football | Liverpool thrash Celtic