學個諺語："You can't have your cake and eat it."

"You can't have your cake and eat it." We use this phrase in English to mean that you can't have something both ways. 

Examples: 

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He's just got married, but he misses the single life. Well it's too bad – you can't have your cake and eat it!

I drank a whole bottle of champagne at the party last night, but now I feel sick - I've got the worst hangover ever. But I suppose you can't have your cake and eat it!

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＂魚與熊掌不可兼得＂，台語中說＂有一好，沒兩好＂。cake除了蛋糕的意思外，還能比喻作（可分配或分割）的利益，變成＂a cake of sth(物)＂，還能指一塊（物）。

From BBC learning English