In fact, half the surface of Earth has been unnaturally engineered so that what lives and what dies there is what we want, which is the reason why you don't have grizzly bears walking through downtown Manhattan.
事实地球上一半的地区 都是人工控制的结果 这些地区我们决定物种的生死。 所以你不可能在曼哈顿的街区 看到灰熊走来走去。