A：How did you do that?
你是怎么办到的?
B：It was a piece of cake.
很简单。
注释：
我们觉得事情很容易就可以做好时，往往会说做那件事简单得像吃饭、喝水一样，正如英文所说：
It is a piece of cake.
= It is a cinch.
(很简单。)
* cinch n.轻松的工作