A: That way they look longer.

B: Now what are you doing?

A: Putting on mascara.

B: Nasty. You'd better not rub your eyes.

A: I won't.

B: And you'd better not cry or you'll have black streaks running down your face.

mascara n.睫毛膏

had better 最好, 还是 ... 好

You had better cross out the last name.

你最好把最后一个名字划掉。

rub vt. 擦,揉

If you keep rubbing, the paint will come off. 你再多擦擦颜色就能掉了.

【参考译文】

A: 这样睫毛看起来会更长。

B: 你这会儿又是在干嘛?

A: 上睫毛膏。

B: 恶心。你最好别揉眼睛。

A: 我才不会。

B: 你也最好别哭，不然你脸上就会有黑道道儿流下来。