cake

cakes and ale

(dated)merrymaking

(旧)寻欢作乐

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.

我从未说过对他进行训练会是小菜一碟。

sell like hot cakes

(informal)be sold quickly and in large quantities

(非正式)销路很好；卖得快又多

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

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

(谚)两者不可兼得