English verb conjugation
CAN DEMONSTRATE

Regular verb: demonstrate - demonstrated - demonstrated

Affirmation

Simple form	V-ing form
I can demonstrate you can demonstrate he can demonstrate we can demonstrate you can demonstrate they can demonstrate	I can be demonstrating you can be demonstrating he can be demonstrating we can be demonstrating you can be demonstrating they can be demonstrating
Perfect	V-ing perfect
I can have demonstrated you can have demonstrated he can have demonstrated we can have demonstrated you can have demonstrated they can have demonstrated	I can have been demonstrating you can have been demonstrating he can have been demonstrating we can have been demonstrating you can have been demonstrating they can have been demonstrating

Negation

Simple form	V-ing form
I can't demonstrate you can't demonstrate he can't demonstrate we can't demonstrate you can't demonstrate they can't demonstrate	I can't be demonstrating you can't be demonstrating he can't be demonstrating we can't be demonstrating you can't be demonstrating they can't be demonstrating
Perfect	V-ing perfect
I can't have demonstrated you can't have demonstrated he can't have demonstrated we can't have demonstrated you can't have demonstrated they can't have demonstrated	I can't have been demonstrating you can't have been demonstrating he can't have been demonstrating we can't have been demonstrating you can't have been demonstrating they can't have been demonstrating

Interrogative form

Simple form	V-ing form
can I demonstrate? can you demonstrate? can he demonstrate? can we demonstrate? can you demonstrate? can they demonstrate?	can I be demonstrating? can you be demonstrating? can he be demonstrating? can we be demonstrating? can you be demonstrating? can they be demonstrating?
Perfect	V-ing perfect
can I have demonstrated? can you have demonstrated? can he have demonstrated? can we have demonstrated? can you have demonstrated? can they have demonstrated?	can I have been demonstrating? can you have been demonstrating? can he have been demonstrating? can we have been demonstrating? can you have been demonstrating? can they have been demonstrating?

Interro-negative form

Simple form	V-ing form
can't I demonstrate? can't you demonstrate? can't he demonstrate? can't we demonstrate? can't you demonstrate? can't they demonstrate?	can't I be demonstrating? can't you be demonstrating? can't he be demonstrating? can't we be demonstrating? can't you be demonstrating? can't they be demonstrating?
Perfect	V-ing perfect
can't I have demonstrated? can't you have demonstrated? can't he have demonstrated? can't we have demonstrated? can't you have demonstrated? can't they have demonstrated?	can't I have been demonstrating? can't you have been demonstrating? can't he have been demonstrating? can't we have been demonstrating? can't you have been demonstrating? can't they have been demonstrating?