Oh, you're being a really good sport about this, Marilyn,
噢,在这件事情上,你倒变成一个看得很开的人, Marilyn?nbsp;
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。