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

Complexity and contradiction are not problems to be solved, but opportunities to be explored.

Technology itself is neither good nor evil; the key lies in the people who use it.

Learning is essentially a matter of stimulus-response connections.

I don't believe in pessimism. If something doesn't come up the way you want, forge ahead. If you think it's going to rain, it will.

最好的老師是那種建議而不是教條化，并激發聽眾自我教學愿望的人。