Definition: If an action or decision is up to someone, they are responsible for doing or making it. Level: B1
杰克，我不能替你决定——这得由你决定。
Jack, I can't decide for you - it's ___be ___up ___to you.
这得由索菲来决定。
It's ___be ___up ___to Sophie to decide.
这只是我的意见——最终决定权在你。
This is just my opinion - the final decision is ___be ___up ___to you.
