You can't have your cake and eat it.

你不能得到你的蛋糕而且吃它。

You can't have your cake and eat it, too.

因为你不能鱼与熊掌兼得。

There is a proverb that says you can't have your cake and eat it too.

有一句谚语是这样说的：鱼与熊掌不可兼得。

You want a regular income but don't want to work. Don't forget: you can't have your cake and eat it!

你既想有稳定的收入，又不想工作。别忘了，鱼和熊掌不可兼得呀！

He can't make up his mind whether to go to college or get a full-time job. You can't have your cake and eat it.

上大学还是找个全日工作的职业，他还拿不定主意，两者不可兼得啊。

You spend all your money on beer and then complain about being poor, but you can't have your cake and eat it, you know.

你把所有的钱都喝啤酒喝完了，然后又抱怨没钱用，你知道，这不能两全其美啊。

But to be fair, I looked it up and it seems that a better translation from the Old English would be “You can't eat your cake and have it too.

但是，为了言之成理，我去查阅了相关资料，从古英语中找到了一个比较靠谱的解释：你无法在吃掉蛋糕后还拥有这块儿蛋糕。

Don't buy a car if you want to walk and stay healthy. You can't eat your cake and have it too.

如果你想要走路、想要保持健康，就别买车。鱼和熊掌不可兼得。

Don't buy a car if you want to walk and stay healthy. You can't eat your cake and have it too.

如果你想步行保持健康，就别买汽车，你可不能两者兼得。