<s>Human: 根据给定的英文短语，写一个3到5句话的段落解释它的意思和用法。
"piece of cake"
</s><s>Assistant: "Piece of cake" is a commonly used English phrase that means something is very easy or effortless to do. For example, if someone asks you if you can complete a task and you know it's easy, you might reply by saying, "Sure, it's a piece of cake." This phrase may have originated from the idea that cake is one of the easiest desserts to bake, so completing a task should be as easy as making a cake. It can also be used to describe a situation where there were no challenges or difficulties encountered. Overall, "piece of cake" is a fun and informal expression that can be used in a variety of situations to describe how easy something is.
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