万物充满了神秘。
Circular economy principles aren't optional—they're essential for survival.
化学的进步以新元素的发现及其性质的测定为标志。
如果不是现在,那是什么时候?如果不是我,那会是谁?
The world is full of obvious things which nobody by any chance ever observes.
The beauty of mathematics only shows itself to more patient followers.