serve a purpose
US /sɜːrv ə ˈpɜːr.pəs/
UK /sɜːrv ə ˈpɜːr.pəs/

1.
役に立つ, 目的を果たす
to be useful or to have a function
:
•
Does this old tool still serve a purpose?
この古い道具はまだ役に立ちますか?
•
Every part of the machine must serve a purpose.
機械のすべての部品は目的を果たす必要があります。