English verb conjugation
CAN CHECK

Regular verb: check - checked - checked

Affirmation

Simple form	V-ing form
I can check you can check he can check we can check you can check they can check	I can be checking you can be checking he 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 he 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 he 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 can't check you can't check he can't check we can't check you can't check they can't check	I can't be checking you can't be checking he can't be checking we can't be checking you can't be checking they can't be checking
Perfect	V-ing perfect
I can't have checked you can't have checked he can't have checked we can't have checked you can't have checked they can't have checked	I can't have been checking you can't have been checking he can't have been checking we can't have been checking you can't have been checking they can't have been checking

Interrogative form

Simple form	V-ing form
can I check? can you check? can he check? can we check? can you check? can they check?	can I be checking? can you be checking? can he 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 he 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 he 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't I check? can't you check? can't he check? can't we check? can't you check? can't they check?	can't I be checking? can't you be checking? can't he be checking? can't we be checking? can't you be checking? can't they be checking?
Perfect	V-ing perfect
can't I have checked? can't you have checked? can't he have checked? can't we have checked? can't you have checked? can't they have checked?	can't I have been checking? can't you have been checking? can't he have been checking? can't we have been checking? can't you have been checking? can't they have been checking?