"you cannot have your cake and eat it" in Chinese (Simplified)
Definition
不能同时享有两个互相矛盾的好处；你若用掉一样东西，就不可能还拥有它。用于某人试图同时拥有两种互不兼容的事物。
Usage Notes (Chinese (Simplified))
这是一句俗语，用来提醒别人不能既要又要，特别是在对方不愿放弃时使用。常用于劝告、讨论选择和权衡时。
Examples
You cannot have your cake and eat it if you want to spend money and save it at the same time.
你如果想一边花钱一边省钱，**鱼与熊掌不可兼得**。
He wants to work less but earn more — well, you cannot have your cake and eat it.
他想工作少但赚更多——**鱼与熊掌不可兼得**。
You cannot have your cake and eat it if you refuse to compromise.
如果你不愿妥协，**你不能既要蛋糕又要吃蛋糕**。
Look, you cannot have your cake and eat it. Sometimes you have to choose one or the other.
看，你**鱼与熊掌不可兼得**。有时候你必须做选择。
I know you want both weekends free and extra pay, but you cannot have your cake and eat it!
我知道你想周末休息还能多拿工资，但**鱼与熊掌不可兼得**。
Everyone dreams of balance, but sometimes you cannot have your cake and eat it — you have to give up something.
每个人都梦想平衡，但有时候**你不能既要蛋糕又要吃蛋糕**——必须放弃点什么。