1. 'When I first got on it I thought it would never work and at a slow speed it's almost impossible to keep upright. 当我第一次驾驶时，我认为它肯定是没办法上路的，而且速度会非常的慢，并且要走直线也是很难的。
2. The park said Tuesday that all its 19 dolphins have been on a low fat diet since late August, when they started failing to hit jumping targets and keep upright while treading water.(See photo) 该公园9月30日说，园内19只海豚在表演时总是无法跳跃到规定高度，游弋时躯体也经常与水面垂直，于是从8月底开始只给它们食用低脂肪食物。
3. Walking keeps you upright and enlists gravity to keep acids from splashing up the esophagus. 散步可以帮助你直立和获得地心重力的作用，去防止胃酸上溅到食道上。
4. In the few hours we spent together, I watched him position her gently in the restaurant booth and later in the back seat of his car, making sure to keep her upright and not to touch her private parts. 我们在一起呆了几个小时，我看到尼森轻轻把她放在餐厅座位上，后来又放到车上后座，保持她上体正直，并小心不去碰不该碰到的地方。
5. Perhaps it's because our visual system evolved to be overly sensitive to even slight departures from the horizontal, to help keep us upright. 可能是由于视觉系统进化，使得我们对些微高于水平面的物体过度敏感，以此帮助我们挺直腰杆。
