a piece of cake

US /ə piːs əv keɪk/
UK /ə piːs əv keɪk/
"a piece of cake" picture
1.

小菜一碟, 轻而易举

something that is very easy to do

:
The exam was a piece of cake; I finished it in half the time.
考试非常简单;我用了一半的时间就完成了。
Learning to ride a bike was a piece of cake for him.
对他来说,学骑自行车轻而易举