The best time to plant a tree was 20 years ago; the second-best time is now.
种一棵树最好的时间是20年前,第二好的时间就是现在。
Don't be afraid to take risks in your career.
物理学的美丽在于它能够用几个简单的方程来描述宇宙。
真相很少是纯粹的,也从不简单。