以物易物、互通有无的倾向是人类共有的,也是其他动物所没有的。
The strong man is strongest when alone.
You put together two people who have not been put together before; and sometimes the world is changed, sometimes not. They may crash and burn, or they may ignite and light up the sky.
这个世界是个美好的地方,值得为之奋斗。