The children haven’t drunk their milk. (This sentence is in the present prefect tense. Many people avoid using the past participle form of "drink." See the examples below.)
You can also use the word "drink" as a noun:
I need a drink of water.
This drink has too much sugar in it.
There were a lot of drinks at the party.
Tom had too many drinks. (Often, using the word "drink" alone means that the drink had alcohol in it.)
We stopped off at the bar for a drink.
The past participle form of "drink" is "drunk." However, the word "drunk" also means "inebriated," or someone has consumed too much alcohol. For this reason, some people avoid using the past participle, "drunk," by choosing a different verb. The verb "have" is a good substitute.
