在观察性研究中，我们常常不得不依赖于无法直接检验的假设。
The city is the greatest human invention, and architects must serve its evolution.
我们靠获得的东西生存。但我们靠给予的东西生活。
译文：做事的时候一定要多替别人着想，读书时一定要切实地下足功夫。赏析：为人处事不能自私自利，不能只顾自己安逸舒适，而要学会换位思考，只有这样，身边才有很多人尊重我们。读书须用功，一字值千金。读书学习要甘于忍受寂寞，才能学有所成。
The artist's responsibility is to create works that stand the test of time.
The discovery of stars orbiting the supermassive black hole at the galactic center was a turning point in astrophysics.
JD.com's values are customer first.
The essence of business is to create value, not just simple transactions.