I can check you can check she can check we can check you can check they can check
V-ing form
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
I can have checked you can have checked she can have checked we can have checked you can have checked they can have checked
V-ing perfect
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
I cannot check you cannot check she cannot check we cannot check you cannot check they cannot check
V-ing form
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
I cannot have checked you cannot have checked she cannot have checked we cannot have checked you cannot have checked they cannot have checked
V-ing perfect
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
can I check? can you check? can she check? can we check? can you check? can they check?
V-ing form
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
can I have checked? can you have checked? can she have checked? can we have checked? can you have checked? can they have checked?
V-ing perfect
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
can I not check? can you not check? can she not check? can we not check? can you not check? can they not check?
V-ing form
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
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?
V-ing perfect
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?