Modal Verbs

List of Modals : Can, Could, Will, Would, Shall, Should, May, Might, Must, Ought To. https://www.perfect-english-grammar.com/modal-verbs.html

https://www.myenglishpages.com/site_php_files/grammar-lesson-modals.php

Past Modals (use HAVE) : https://www.perfect-english-grammar.com/could-have-should-have-would-have.html

Test yourself : https://www.englishpage.com/modals/modalintro.html