Yes, we have done a little. But we have just started and have nothing to show you.
有,我们做了一些,但是因为我们才刚起步,并没有任何资料可以提供给你们。
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。