hair是可數名詞還是不可數名詞

例句：

1、She walked forward and embraced him and stroked his tousled white hair.

她走上前擁抱他並輕撫他凌亂的白髮。

2、Applying the dye can be messy, particularly on long hair.

塗抹染髮劑可能會搞得一團糟，特別是長髮。

3、His long, uncovered hair flew back in the wind.

他那露在外面的長髮隨風向後飛舞。

4、He was a tall, thin man with grey hair.

他是個瘦高個，頭髮灰白。