English verb conjugation
CAN CHECK

Regular verb: check - checked - checked

Affirmation

Simple form	V-ing form
I can check you can check she can check we can check you can check they can check	I can be checking you can be checking she can be checking we can be checking you can be checking they can be checking
Perfect	V-ing perfect
I can have checked you can have checked she can have checked we can have checked you can have checked they can have checked	I can have been checking you can have been checking she can have been checking we can have been checking you can have been checking they can have been checking

Negation

Simple form	V-ing form
I cannot check you cannot check she cannot check we cannot check you cannot check they cannot check	I cannot be checking you cannot be checking she cannot be checking we cannot be checking you cannot be checking they cannot be checking
Perfect	V-ing perfect
I cannot have checked you cannot have checked she cannot have checked we cannot have checked you cannot have checked they cannot have checked	I cannot have been checking you cannot have been checking she cannot have been checking we cannot have been checking you cannot have been checking they cannot have been checking

Interrogative form

Simple form	V-ing form
can I check? can you check? can she check? can we check? can you check? can they check?	can I be checking? can you be checking? can she be checking? can we be checking? can you be checking? can they be checking?
Perfect	V-ing perfect
can I have checked? can you have checked? can she have checked? can we have checked? can you have checked? can they have checked?	can I have been checking? can you have been checking? can she have been checking? can we have been checking? can you have been checking? can they have been checking?

Interro-negative form

Simple form	V-ing form
can I not check? can you not check? can she not check? can we not check? can you not check? can they not check?	can I not be checking? can you not be checking? can she not be checking? can we not be checking? can you not be checking? can they not be checking?
Perfect	V-ing perfect
can I not have checked? can you not have checked? can she not have checked? can we not have checked? can you not have checked? can they not have checked?	can I not have been checking? can you not have been checking? can she not have been checking? can we not have been checking? can you not have been checking? can they not have been checking?