https://learnenglishteens.britishcouncil.org/grammar/a1-a2-grammar/have-must-should-obligation-advicehttps://www.esllessonhandouts.com/handout/talking-about-obligation/
https://learnenglishteens.britishcouncil.org/grammar/a1-a2-grammar/past-simple-irregular-verbs
https://learnenglishteens.britishcouncil.org/grammar/a1-a2-grammar/past-simple-regular-verbs
https://learnenglish.britishcouncil.org/grammar/b1-b2-grammar/past-perfect
https://learnenglishteens.britishcouncil.org/skills/listening/a1-listening/describing-people
