I can boil you can boil she can boil we can boil you can boil they can boil
V-ing form
I can be boiling you can be boiling she can be boiling we can be boiling you can be boiling they can be boiling
Perfect
I can have boiled you can have boiled she can have boiled we can have boiled you can have boiled they can have boiled
V-ing perfect
I can have been boiling you can have been boiling she can have been boiling we can have been boiling you can have been boiling they can have been boiling
Negation
Simple form
I cannot boil you cannot boil she cannot boil we cannot boil you cannot boil they cannot boil
V-ing form
I cannot be boiling you cannot be boiling she cannot be boiling we cannot be boiling you cannot be boiling they cannot be boiling
Perfect
I cannot have boiled you cannot have boiled she cannot have boiled we cannot have boiled you cannot have boiled they cannot have boiled
V-ing perfect
I cannot have been boiling you cannot have been boiling she cannot have been boiling we cannot have been boiling you cannot have been boiling they cannot have been boiling
Interrogative form
Simple form
can I boil? can you boil? can she boil? can we boil? can you boil? can they boil?
V-ing form
can I be boiling? can you be boiling? can she be boiling? can we be boiling? can you be boiling? can they be boiling?
Perfect
can I have boiled? can you have boiled? can she have boiled? can we have boiled? can you have boiled? can they have boiled?
V-ing perfect
can I have been boiling? can you have been boiling? can she have been boiling? can we have been boiling? can you have been boiling? can they have been boiling?
Interro-negative form
Simple form
can I not boil? can you not boil? can she not boil? can we not boil? can you not boil? can they not boil?
V-ing form
can I not be boiling? can you not be boiling? can she not be boiling? can we not be boiling? can you not be boiling? can they not be boiling?
Perfect
can I not have boiled? can you not have boiled? can she not have boiled? can we not have boiled? can you not have boiled? can they not have boiled?
V-ing perfect
can I not have been boiling? can you not have been boiling? can she not have been boiling? can we not have been boiling? can you not have been boiling? can they not have been boiling?