【英语时差8,16】空中舞蹈

 By bending arms and legs or angling her body–presenting more or less surface area to the ground–she can change her rate of fall, slowing or speeding up her terminal velocity¹ around ten or twenty miles per hour. To fall as fast as two hundred miles per hour, a skydiver goes into either a diving or a standing² up posture³. This presents the least surface area downward, so her terminal velocity is highest. How Skydivers Land When a skydiver opens her chute, she’s increasing the amount of surface area she presents to the ground dramatically. Her terminal velocity slows enough for a soft landing.

1 velocity   

n.速度，速率

参考例句：

• Einstein's theory links energy with mass and velocity of light.爱因斯坦的理论把能量同质量和光速联系起来。
• The velocity of light is about 300000 kilometres per second.光速约为每秒300000公里。

2 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

3 posture   

n.姿势，姿态，心态，态度；v.作出某种姿势

参考例句：

• The government adopted an uncompromising posture on the issue of independence.政府在独立这一问题上采取了毫不妥协的态度。
• He tore off his coat and assumed a fighting posture.他脱掉上衣，摆出一副打架的架势。