a piece of cake

释义：“小菜一碟”。在留学文书里形容极容易完成的任务或项目，往往是为后续的转折作为铺垫和反衬。

例句：
Heidi made it seem as if losing the baby weight was a piece of cake.
Being a senior executive at a multinational corporation is a piece of cake next to being a fulltime mom.