be welcome to idiom informal
可以随便拥有，可以随意做（尤指那些不被别人看重的东西或事）
If someone is welcome to someone or something, they can have it or do it, especially because it is not wanted by anyone else.
You're welcome to it - I can never get it to work right. 你尽管用——我就从没能让它正常运转过。
If they want to change the rules, they are welcome to try. 如果他们想改变规则，尽可以试试。