mouse是可数名词吗

　　Click the left mouse button twice to highlight the program.

　　双击鼠标左键来加亮突出这个程序。

　　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。