环境是一个长期问题，需要长期承诺。
The environment is a long-term issue that requires long-term commitment.
The idea of America is so important to me. It's about freedom, democracy, and the ability to create your own destiny.
Never stop learning; the moment you do, you stop growing.
谦逊是科学家所能拥有的最大美德。
婴儿的哭声与其听起来一样严重。