Piece of cake
Something that is easy
Something difficult to do
Raining cats and dogs
Go to sleep
A heavy rain
Once in a blue moon
To happen rarely
To never happen
When pigs fly
Activity that always happens
Activity that never happens
Under the weather
To feel sick or sad
To feel very very happy
Bite more that you can chew
To do many activities
To be lazy
Crack someone up
To make someone cry
To make someone laugh
Back to square one
To do something perfectly
Start again
Go the extra mile
To make an effort
To not do anything
Gut feeling
A good intuition
A bad intuition
Hit the books
To not read books
To study
Hit the hay
Go to sleep
To wake up early
