【英语时差8,16】让地球转起来（上）

We all know that humans have quite a knack¹ for changing the natural environment. In spite of this, you probably think some things are simply too fundamental for human activity to affect. For instance, most people would imagine that the Earth’s twenty-four hour rotation² would be immune to our tampering³. As it turns out, this isn’t the case. We’ve sped our planet up. How fast anything spins is partly determined⁴ by how its mass is distributed. The closer an object’s mass is to its axis⁵ of rotation, the faster it spins. To picture this, imagine an ice skater doing a pirouette. When her arms are extended, she spins slowly and gracefully⁶. But when she draws her arms inward, she spins much faster. It took more energy to start spinning with her arms extended, so as she draws them in, that extra energy is converted into faster spinning.

1 knack   

n.诀窍，做事情的灵巧的，便利的方法

参考例句：

• He has a knack of teaching arithmetic.他教算术有诀窍。
• Making omelettes isn't difficult,but there's a knack to it.做煎蛋饼并不难，但有窍门。

2 rotation   

n.旋转；循环，轮流

参考例句：

• Crop rotation helps prevent soil erosion.农作物轮作有助于防止水土流失。
• The workers in this workshop do day and night shifts in weekly rotation.这个车间的工人上白班和上夜班每周轮换一次。

3 tampering   

v.窜改( tamper的现在分词 )；篡改；（用不正当手段）影响；瞎摆弄

参考例句：

• Two policemen were accused of tampering with the evidence. 有两名警察被控篡改证据。 来自《简明英汉词典》
• As Harry London had forecast, Brookside's D-day caught many meter-tampering offenders. 正如哈里·伦敦预见到的那样，布鲁克赛德的D日行动抓住了不少非法改装仪表的人。 来自辞典例句

4 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

5 axis   

n.轴，轴线，中心线；坐标轴，基准线

参考例句：

• The earth's axis is the line between the North and South Poles.地轴是南北极之间的线。
• The axis of a circle is its diameter.圆的轴线是其直径。

6 gracefully   

ad.大大方方地；优美地

参考例句：

• She sank gracefully down onto a cushion at his feet. 她优雅地坐到他脚旁的垫子上。
• The new coats blouse gracefully above the hip line. 新外套在臀围线上优美地打着褶皱。