在没有航海图的海域上航行是需要勇气的。

A prophet is not without honor except in his own country and in his own house

"The past is a shadow that follows us, but it is also a light that guides us."

Precision measurements in astronomy open new windows to understanding the universe.

The periodic table hasn't changed, but how we use its elements must.

You are never too old to set another goal or to dream a new dream.