mice本身就是mouse的复数.

mouse

n.老鼠;耗子;鼠标

复数： mice

例句：

Mice are born naked.

老鼠出生时遍体无毛。

The stores were overrun with rats and mice.

仓库里到处都是大大小小的老鼠。

Our cat is hopeless at catching mice.

我们的猫绝对捉不到老鼠。

The house was completely overrun with mice.

这房子简直成了老鼠的天下。