A great infographic by Kaplan International Colleges on School idioms:

Kaplan International

Example sentences with these idioms:

• BOOKWORM
  Margaret rarely leaves the library. She has typical symptoms of a bookworm.
  
• TO BRAINSTORM
  Over the next three days, we’ll hear stories of bravery and brainstorm solutions for change.
  
• COPYCAT
  She called me a copycat for wearing the same prom dress.
• HIT THE BOOKS
  I haven’t studied for today’s test yet. Time to hit the books!
  
• PASS WITH FLYING COLORS
  As for the exam, I’m pleased to report you passed with flying colors.
• SKIP CLASS
  Are you going to skip class and go to the beach?
• DROPOUT
  “Why don’t we see Joanne Red at school anymore?”
  “Oh, she’s a dropout, she left high school last week.”
• TEACHER’S PET
  Marcus is a teacher’s pet. He cannot shut up. He runs to the class after lunch and seems to always be raising his hand.

A funny video by English is Fun! on this topic:

• A POP QUIZ => An unexpected exam.
• TO READ OUT LOUD => To read loud enough that anyone can hear you and follow along.
• TO PLAY HOOKY => To not go to school when you’re supposed to.
• CLASS CLOWN => The person in the class who just likes to act silly and make everyone laugh during class.

Now that you know all these idioms, try to fill the gaps in this quiz to find out if you remember their meanings:

Activity for teachers: School idioms ex.
Answers: School idioms ex. answers