mouse的复数形式为什么是mice

　　He was a weak little mouse of a man.

　　他是个懦弱无能的人。

　　A cat often plays with a mouse before the kill.

　　猫在咬死老鼠之前常常要耍弄它一番。

　　I held the mouse by its tail.

　　我抓着耗子的尾巴倒提起来。

　　Select the text you want to format by holding down the left button on your mouse.

　　按住鼠标左键选取你想要格式化的文本。

　　Choose 'printer' from the menu and click with the right mouse button.

　　从菜单上选取“打印机”，然后点击鼠标右键。