A few 'bad apples' cheated on the test, and now everyone has to take the test again.
a bad/rotten 'apple' [=an apple that has rotted and cannot be eaten]
Everything in the cupboard was (arranged) 'in apple-pie order'.
(..) All right, Mr. Clarke. Yeah, I'll see you on Monday. I'll see you on Monday, Mr. Clarke. Bye. Do you still have that kiddie pool we bobbed for apples in? - I think so. Yeah. - Yeah. Good. Then we just need salt. Lots of it. How much is "lots"? (..)2016 TvShow: Stranger Things Title: Chapter Seven: The Bathtub Season: 1 Episode 7