Rigor in proof is what separates mathematics from all other sciences.
可持续发展不再是可选项;它是任何希望在未来蓬勃发展的企业的必需品。
I have always believed that the way you treat others is a reflection of how you feel about yourself.
The greatest sweetener of human life is Friendship. To raise this to the highest pitch of enjoyment, is a secret which but few discover.