We're Killing Ourselves, in which he tries to sketch life in the year 2000.
“我们正在自杀”,在这本书中他简述了2000年的生活。
and we have only to turn to that extraordinary discovery of echo-location in bats to see a case in which the voice plays a strictly utilitarian role.
我们只要看一看蝙蝠回声定位这一极不寻常的发现,就可以探究一下声音在什么情况下有绝对的实用价值。