as quiet as a mouse

例句：

1. 1.The room was so quiet that I couldhear the sound of my own breathing.
   房间非常安静，我甚至能听到自己的呼吸声。
2. 2. She sat quietly in her chair, not saying a word.
   她静静地坐在椅子上，一句话也没说。
3. 3. Thelittle girl was so quietthat she seemed to be sleeping.
   那个小女孩非常安静，好像在睡觉。