hair的一般用复数还是单数,hair前面用is还是are

一般用作单数形式，为不可数名词，中文意思是n. 毛发，（尤指）头发；些微；（植物叶茎上的）茸毛

Her hair was perfectly coiffed.她的头发是精心打理过的。

She was playing with her hair.她在抚弄自己的头发。

Careful—you're messing my hair.小心—你弄乱我的头发了。