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

Will you be clever at the expense of others， or will you be kind？

The most important thing in science is not so much to obtain new facts as to discover new ways of thinking about them.

Innovation distinguishes between a leader and a follower.

如果你不愿意學習，沒人能幫你。如果你決心學習，沒人能阻止你。