English verb conjugation
CAN SKETCH

Regular verb: sketch - sketched - sketched

Affirmation

Simple form	V-ing form
I can sketch you can sketch he can sketch we can sketch you can sketch they can sketch	I can be sketching you can be sketching he can be sketching we can be sketching you can be sketching they can be sketching
Perfect	V-ing perfect
I can have sketched you can have sketched he can have sketched we can have sketched you can have sketched they can have sketched	I can have been sketching you can have been sketching he can have been sketching we can have been sketching you can have been sketching they can have been sketching

Negation

Simple form	V-ing form
I can't sketch you can't sketch he can't sketch we can't sketch you can't sketch they can't sketch	I can't be sketching you can't be sketching he can't be sketching we can't be sketching you can't be sketching they can't be sketching
Perfect	V-ing perfect
I can't have sketched you can't have sketched he can't have sketched we can't have sketched you can't have sketched they can't have sketched	I can't have been sketching you can't have been sketching he can't have been sketching we can't have been sketching you can't have been sketching they can't have been sketching

Interrogative form

Simple form	V-ing form
can I sketch? can you sketch? can he sketch? can we sketch? can you sketch? can they sketch?	can I be sketching? can you be sketching? can he be sketching? can we be sketching? can you be sketching? can they be sketching?
Perfect	V-ing perfect
can I have sketched? can you have sketched? can he have sketched? can we have sketched? can you have sketched? can they have sketched?	can I have been sketching? can you have been sketching? can he have been sketching? can we have been sketching? can you have been sketching? can they have been sketching?

Interro-negative form

Simple form	V-ing form
can't I sketch? can't you sketch? can't he sketch? can't we sketch? can't you sketch? can't they sketch?	can't I be sketching? can't you be sketching? can't he be sketching? can't we be sketching? can't you be sketching? can't they be sketching?
Perfect	V-ing perfect
can't I have sketched? can't you have sketched? can't he have sketched? can't we have sketched? can't you have sketched? can't they have sketched?	can't I have been sketching? can't you have been sketching? can't he have been sketching? can't we have been sketching? can't you have been sketching? can't they have been sketching?