reflection可以作可数，也可以作不可数用。
N-COUNT （镜子里的）映像;（水中的）倒影A reflection is an image that you can see in a mirror or in glass or water.
Meg stared at her reflection in the bedroom mirror.
梅格注视着卧室中镜子里的自己。
N-UNCOUNT （光或热等的）反射Reflection is the process by which light and heat are sent back from a surface and do not pass through it.
...the reflection of a beam of light off a mirror.
一束光从镜子表面的反射
