色多多在线观看播放-色多多在线观看高清免费-色多多在线观看视频-色多多在线看-欧美aaaaa性bbbbb小妇-欧美aaaav免费大片

Collaboration is key to solving the complex energy challenges we face today.

To do mathematics is to explore a universe of ideas, where the only limit is your imagination.

The test of a first-rate intelligence is the ability to hold two opposed ideas in mind at the same time and still retain the ability to function.

你不必完美也能很了不起。

催化不僅僅是讓反應更快，而是讓反應更好。

Mathematics knows no races or geographic boundaries; for mathematics, the cultural world is one country.