English verb conjugation
CAN HARKEN

Regular verb: harken - harkened - harkened

Affirmation

Simple form	V-ing form
I can harken you can harken he can harken we can harken you can harken they can harken	I can be harkening you can be harkening he can be harkening we can be harkening you can be harkening they can be harkening
Perfect	V-ing perfect
I can have harkened you can have harkened he can have harkened we can have harkened you can have harkened they can have harkened	I can have been harkening you can have been harkening he can have been harkening we can have been harkening you can have been harkening they can have been harkening

Negation

Simple form	V-ing form
I can't harken you can't harken he can't harken we can't harken you can't harken they can't harken	I can't be harkening you can't be harkening he can't be harkening we can't be harkening you can't be harkening they can't be harkening
Perfect	V-ing perfect
I can't have harkened you can't have harkened he can't have harkened we can't have harkened you can't have harkened they can't have harkened	I can't have been harkening you can't have been harkening he can't have been harkening we can't have been harkening you can't have been harkening they can't have been harkening

Interrogative form

Simple form	V-ing form
can I harken? can you harken? can he harken? can we harken? can you harken? can they harken?	can I be harkening? can you be harkening? can he be harkening? can we be harkening? can you be harkening? can they be harkening?
Perfect	V-ing perfect
can I have harkened? can you have harkened? can he have harkened? can we have harkened? can you have harkened? can they have harkened?	can I have been harkening? can you have been harkening? can he have been harkening? can we have been harkening? can you have been harkening? can they have been harkening?

Interro-negative form

Simple form	V-ing form
can't I harken? can't you harken? can't he harken? can't we harken? can't you harken? can't they harken?	can't I be harkening? can't you be harkening? can't he be harkening? can't we be harkening? can't you be harkening? can't they be harkening?
Perfect	V-ing perfect
can't I have harkened? can't you have harkened? can't he have harkened? can't we have harkened? can't you have harkened? can't they have harkened?	can't I have been harkening? can't you have been harkening? can't he have been harkening? can't we have been harkening? can't you have been harkening? can't they have been harkening?