I'm too tired because i sleep late in the night
Hit the sack
To tell someone people secret information
Spill the beans
Is when you feel ill
Under the weather
That something was easier than they think
A piece of cake
When an event was too expensive
Cost an arm and a leg
When people thinks the same of each other when they see each other
See eye to eye
Decide that you finsished something
Call it a day
The last problem of a situation
The last straw
When something is never going to past
When pigs fly
Its for relaxing before an important event (like a presentation or exam)
Break a leg