【网络综合 - 英语口语资料】：
A Piece Of Cake “A Piece Of Cake ”用来表示非常容易的事。
Something that is very easy to do is “a piece of cake”。 Example： “Can you finish your homework in ten minutes？” Reply： “It will be a piece of cake.” “A piece of cake” is so easy to do that it is like eating a piece of cake. Example： “How was your test today？” Reply： “It was a piece of cake.” You say “piece of cake” to show how very easy it is for you to do something. Example： “I've always had a hard time studying history， but math is a piece of cake.” You are very confident that you can do something which you think is a piece of cake. Example： “Do you expect to win your tennis match today？” Reply： “It will be a piece of cake.”
