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