He strolled like a man in the park without a care or a worry in the world. Like he had>

The only limit to our realization of tomorrow will be our doubts of today.

To understand the electron is to understand the foundation of our technological civilization.

人无远虑，必有近忧。如果做事没有计划，毫无思想准备，就不能从容应付突如其来的事情。