Something easy
A piece of cake
Important person
A big fish
Feel nervous
Butterflies in the stomach
Raining hard
Raining cats and dogs
Small part of something
Drop in the bucket
Can't change who you are
A leopard can't change his spots.
Something visual says more than words.
A picture paints a thousand words.
Be patient
Hold your horses
Study
Hit the books
Sleep like a baby
Have a deep sleep
All ears
To listen carefully
Can't judge a book by its cover
Can't judge something or someone by its appereance
Curiosity killed the cat
Being inquisitive can lead to unpleasent situations
Hit the sack
Go to sleep
