mouth的現(xiàn)在分詞怎么變化

　　例句：

　　She opened her mouth to say something.

　　她張開(kāi)嘴要說(shuō)什么。

　　He hardly ever opens his mouth.

　　他幾乎從不開(kāi)口。

　　Then he made his way to the tunnel mouth.

　　于是他走到隧道入口。