People change and forget to tell each other.
宇宙是无限多样的。
The Langlands program is a challenge to the limits of human understanding.
这个世界惟有两样东西让我们的心灵感到深深的震撼，一是我们头顶上灿烂的星空,一是我们内心崇高的道德法则。
Certification schemes are the grammar of responsible forestry—they give structure to our good intentions.