Caught red-handed
To be caught in the act of doing somethignwrong
Raining cats and dogs
Raining very heavily
It costs an arm and a leg
To be very expensive and/or overpriced
Have money to burn
Fish out of water
to be out of your usual environment
Under the weather
To be feeling sick or unwell
Piece of cake
A way of saying that something is very easy
Fit as a fiddle
To be in good shape
Head over heels
To be completely into something (usually in love)
Call it a day
To finish or stop doing something
Let the cat out of the bag
To reveal a secret by accident
Time is money
Time is valuable
Spill the beans
To reveal a secret
The early bird gets the worm
It is better to start something early
To be exactly correct
Over the moon
Very happy/excitd
Break a leg!
A way of wishing someone good luck
Once in a blue moon
Very rarely
Get your ducks in a row
To prepare before you do something
Don't cry over spilled milk
There's no point in being upset about what can't be changed