Without ecological balance, there is no real economic benefit.

We are on the verge: Today our program proved Fermat's next-to-last theorem.

合抱的大树由细小的幼苗长成，九层的高台由一筐筐泥土堆起，千里远行从脚下第一步开始

We all live in the past, we take a minute to know someone, an hour to like someone , a day to love someone , but a whole life to forget someone.