数学不是观赏性运动——你必须参与其中才能欣赏它的美。

The most difficult thing is to be simple.

All men have the stars， but they are not the same things for different people。 For some， who are travelers， the stars are guides。 For others they are no more than little lights in the sky。 For others， who are scholars， they are problems。 For my businessman they were wealth。 But all these stars are silent。 You – you alone – will have the stars as no one else has them.