"She drinks water."
Translation:Cô ấy uống nước.
Vietnamese has a number of different pronouns for "you," each for a different audience. To turn a "you" into an impersonal pronoun (like he/she), you can just add ấy after it.
Cô is actually a word that can be used to address women (usually women who are older than you). To create the pronoun "she," cô and ấy are combined to make "cô ấy."
Would you still use cô ấy if you were referring to a younger girl or an old lady?