English verb conjugation
COULD BOIL

Regular verb: boil - boiled - boiled

Affirmation

Simple form	V-ing form
I could boil you could boil he could boil we could boil you could boil they could boil	I could be boiling you could be boiling he could be boiling we could be boiling you could be boiling they could be boiling
Perfect	V-ing perfect
I could have boiled you could have boiled he could have boiled we could have boiled you could have boiled they could have boiled	I could have been boiling you could have been boiling he could have been boiling we could have been boiling you could have been boiling they could have been boiling

Negation

Simple form	V-ing form
I could not boil you could not boil he could not boil we could not boil you could not boil they could not boil	I could not be boiling you could not be boiling he could not be boiling we could not be boiling you could not be boiling they could not be boiling
Perfect	V-ing perfect
I could not have boiled you could not have boiled he could not have boiled we could not have boiled you could not have boiled they could not have boiled	I could not have been boiling you could not have been boiling he could not have been boiling we could not have been boiling you could not have been boiling they could not have been boiling

Interrogative form

Simple form	V-ing form
could I boil? could you boil? could he boil? could we boil? could you boil? could they boil?	could I be boiling? could you be boiling? could he be boiling? could we be boiling? could you be boiling? could they be boiling?
Perfect	V-ing perfect
could I have boiled? could you have boiled? could he have boiled? could we have boiled? could you have boiled? could they have boiled?	could I have been boiling? could you have been boiling? could he have been boiling? could we have been boiling? could you have been boiling? could they have been boiling?

Interro-negative form

Simple form	V-ing form
could I not boil? could you not boil? could he not boil? could we not boil? could you not boil? could they not boil?	could I not be boiling? could you not be boiling? could he not be boiling? could we not be boiling? could you not be boiling? could they not be boiling?
Perfect	V-ing perfect
could I not have boiled? could you not have boiled? could he not have boiled? could we not have boiled? could you not have boiled? could they not have boiled?	could I not have been boiling? could you not have been boiling? could he not have been boiling? could we not have been boiling? could you not have been boiling? could they not have been boiling?