English has various food-related idioms and apples are no exception:
1. His granddaughter is the "apple of his eye" - She is his favorite. He loves her very much.
2. That test was "as easy as pie" - The test was very easy.
3. He is a "bad apple" - He is a bad person. He has bad behavior compared to the others.
4. That is like "comparing apples and oranges" - That is like comparing two very different things.
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