Which idiom is used to describe that children are not well educated?

1. No class: class: education, teaching. Can't educate someone.

2. Do not change after repeated education? [lǐ jià obgi]: I have been educated many times, but I still don't correct it.

3. Stubborn? [zhí mí bù wù]: Insist on mistakes without knowing it.

4. Do not change after repeated education? [lě ijià o bü gi]: Repeated teaching does not change.

5. Never repent? 【 ǐǐǐǐǐǐ I 】: Never regret or correct until you die. Describe very stubborn.

6. No repentance? [bù zhī hu ǐ g ǐ i]: I don't know how to correct my mistakes.