无限小在自然中的作用是无限大的。
Never look back unless you are planning to go that way.
我们不是从祖先那里继承了海洋,而是从子孙那里借用了它们。
The dog is called Sandy. I like Sandy. He is not clever but he is very cheerful.
我们不仅仅是在制造产品,我们的每个决定都在塑造地球的未来。