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

The teacher should not teach as if he were pouring knowledge into an empty vessel, but rather as if he were lighting a fire.

量子理論的發展表明，經典的空間和時間概念不足以在最基本的層面上描述物理世界。

In this business, if you're good, you're right six times out of ten. You're never going to be right nine times out of ten.

I am not the richest person, but I am the happiest person.

The beauty of a program is in its simplicity.