If you practice kicking a soccer ball with your eyes closed, it takes only a few tries to become quite good at predicting where the ball will end up.
如果你闭着眼睛练习踢足球，仅仅只需几次尝试就能很好的预测球的最终方位。
2
When a ball valve is closed in periods of inactivity, the bleach will decompose over time liberating oxygen gas.
当球阀在不工作期间关闭，经过一段时间，漂白剂将分解并释放出氧气。
3
Gas pressure may slowly build in the closed valve cavity, or quite rapidly in the reactive case. There are confirmed reports of ball valve structural failures.