A shoal of fish will do this.

鱼群也反射声音。

he is lending the bank money, repayment of which he may demand at any time,

就等于把钱借给了银行。这笔钱他可以随时提取，

But, of the vertebrates, unpredictable Nature selected only snakes (and one lizard).

不过，当它们相互撕打时，毒液就成了利弊参半的武，可以杀死对方，也可以被对方的毒液杀死。

The majority of thepatients attending the medical out-patients departments of our hospitals

在医院门诊部看病的大多数人

Such a loss of dignity and descent into childish behaviour on the part of the adults deeply shocks the adolescents,

这种有失身份和孩子气的作法使青春期的孩子大为震惊，

do in fact run out of energy in accordance with the second law of thermodynamics (whether the whole universe does so is a moot point at present).

也都会消耗完其能量（整个宇宙是否如此，目前尚有争论）。