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

Mathematics is the language of the universe, and through it, we can understand the fundamental principles that govern our world.

The biggest risk is not taking any risk. In a world that's changing quickly, the only strategy that is guaranteed to fail is not taking risks.

歷史不是發生過的事，歷史只是歷史學家告訴我們的故事。