The baby's cutting a tooth. That's why she's crying. 这个婴儿正在长牙,难怪她哭个没完。
How old are babies when they cut their first tooth?
Every time one of her babies cuts their teeth, she's up all night soothing them.
I can't believe Lily is cutting her first tooth already!
Tom's chewing everything in sight - I think he's probably cutting a tooth.
Oh look! Patrick's cut another tooth!
See also: cut verb (GROW TEETH)