my mum has three white hair改错

My mum has three white hairs.
hair这个词既可以是可数名词,也可以是不可数名词,只是含义稍有变化：
1.作为可数名词,是指一根一根的“头发”或“毛发”：
Look at this,a hair in my soup.你瞧,我的汤里有根头发.
The cat has left her loose hairs all over my clothes.猫掉的毛弄得我衣服上到处都是.
My father has quite a few gray hairs.我父亲已有不少白发.
There is not a gray hair on his head.他头上没有一根白头发.
2.作为不可数名词“头发”的总称,是集合名词：
I’ll have my hair cut.我要去理发.
He has blond hair.他有一头金发.
She has a beautiful head of hair.她有一头漂亮的头发.
The woman likes to do her hair in foreign style.这个女人喜欢把头发梳成外国式.
试比较以下句子：
He has grey hair.他满头白发.
He has grey hairs.他有些白发了.