判断两个λ表达式是否等价的问题是无法解决的。

The permanence of certain urban artifacts gives them the quality of monuments.

在科学中最激动人心的短语，预示着新发现的，不是“我找到了！”而是“这有点奇怪……”

The best way to predict the future is to invent it. In energy, that means developing new technologies and new business models.

Purchase the most recent tourist guidebook to your home town or region. You’ll learn a lot by playing the tourist once a year.

病毒的复杂性提醒我们，关于生物学我们还有很多需要学习。

Speech is a kind of action， and our words are the tools we use to perform it.