English verb conjugation
SHOULD WARN

Regular verb: warn - warned - warned

Affirmation

Simple form	V-ing form
I should warn you should warn he should warn we should warn you should warn they should warn	I should be warning you should be warning he should be warning we should be warning you should be warning they should be warning
Perfect	V-ing perfect
I should have warned you should have warned he should have warned we should have warned you should have warned they should have warned	I should have been warning you should have been warning he should have been warning we should have been warning you should have been warning they should have been warning

Negation

Simple form	V-ing form
I should not warn you should not warn he should not warn we should not warn you should not warn they should not warn	I should not be warning you should not be warning he should not be warning we should not be warning you should not be warning they should not be warning
Perfect	V-ing perfect
I should not have warned you should not have warned he should not have warned we should not have warned you should not have warned they should not have warned	I should not have been warning you should not have been warning he should not have been warning we should not have been warning you should not have been warning they should not have been warning

Interrogative form

Simple form	V-ing form
should I warn? should you warn? should he warn? should we warn? should you warn? should they warn?	should I be warning? should you be warning? should he be warning? should we be warning? should you be warning? should they be warning?
Perfect	V-ing perfect
should I have warned? should you have warned? should he have warned? should we have warned? should you have warned? should they have warned?	should I have been warning? should you have been warning? should he have been warning? should we have been warning? should you have been warning? should they have been warning?

Interro-negative form

Simple form	V-ing form
should I not warn? should you not warn? should he not warn? should we not warn? should you not warn? should they not warn?	should I not be warning? should you not be warning? should he not be warning? should we not be warning? should you not be warning? should they not be warning?
Perfect	V-ing perfect
should I not have warned? should you not have warned? should he not have warned? should we not have warned? should you not have warned? should they not have warned?	should I not have been warning? should you not have been warning? should he not have been warning? should we not have been warning? should you not have been warning? should they not have been warning?