tears与tear什么时候用tear 什么时候用tears 表示流泪哪个用于表示“泪奔”

tear的复数形式TEARS
n. 眼泪
The hot tears welled up in her eyes.
热泪涌上她的眼眶。
TAER
n. 眼泪，（撕破的）洞或裂缝，撕扯
The memory of his dead mother brought tears to his eyes.
他忆起去世的母亲便热泪盈眶.
vt（及物动词） 撕掉，扯下，扰乱
tear a sheet of paper in two 把一张纸撕成两半
vi（不及物动词） 流泪，撕破
This material tears easily.
这种料子很容易撕破。
泪奔 tears ran

单数用tear,
复数用tears.
当然，tear也有撕扯的意思。
My wife burst into tears when she heard the bad news.
我太太听到这个坏消息就哭了起来。
Don't pull the pages so hard or they will tear.
别那麽使劲扯书页，那会撕破的。

tear 是单数,眼泪的话通常是 a tear,
e.g.
she did not shed a tear.
A teardrop
tears 是复数,比较常用
e.g
Tears are welling up in her eyes.