cakes and ale

(dated)merrymaking

(舊)尋歡作樂

a piece of cake

(informal)something easily achieved

(非正式)容易的事

I never said that training him would be a piece of cake.

我從未說過對他進行訓練會是小菜一碟。

sell like hot cakes

(informal)be sold quickly and in large quantities

(非正式)銷路很好；賣得快又多

you can't have your cake and eat it (too)

(proverb)you can't enjoy both of two desirable but mutually exclusive alternatives

(諺)兩者不可兼得