It's a piece of cake

It's a piece of cake. 

껌이야~

 

This is by bread and butter.

이게 내 밥줄이야.

 

He is the apple of my eye.

내게 가장 소중한 존재에요.(apple=> 눈동자)

(눈 중 눈동자라는 뜻)

 

We are packed like sardines.

사람으로 꽉 찼어요. 

 

That's the way the cookie crumbles.

세상일이 다 그렇죠. 뭐.