C1 Grammar

Modals in the past

Used to & would:

https://www.examenglish.com/grammar/used_to_would.htm

Have to:

https://www.examenglish.com/grammar/A2_have_to.htm

Should have:

https://www.examenglish.com/grammar/B1_should_have.htm

May, Might and adverbs or probability

https://www.examenglish.com/grammar/b1_may_might.htm

Should & Ought to

https://www.examenglish.com/grammar/A2_ShouldOught.htm

Can/ Could

https://www.examenglish.com/grammar/A2_can_could.htm

Modals compilation

http://www.ompersonal.com.ar/ADVANCED/unit12/page3.htm