English verb conjugation
CAN JACKKNIFE

Regular verb: jackknife - jackknifed - jackknifed

Affirmation

Simple form	V-ing form
I can jackknife you can jackknife he can jackknife we can jackknife you can jackknife they can jackknife	I can be jackknifing you can be jackknifing he can be jackknifing we can be jackknifing you can be jackknifing they can be jackknifing
Perfect	V-ing perfect
I can have jackknifed you can have jackknifed he can have jackknifed we can have jackknifed you can have jackknifed they can have jackknifed	I can have been jackknifing you can have been jackknifing he can have been jackknifing we can have been jackknifing you can have been jackknifing they can have been jackknifing

Negation

Simple form	V-ing form
I can't jackknife you can't jackknife he can't jackknife we can't jackknife you can't jackknife they can't jackknife	I can't be jackknifing you can't be jackknifing he can't be jackknifing we can't be jackknifing you can't be jackknifing they can't be jackknifing
Perfect	V-ing perfect
I can't have jackknifed you can't have jackknifed he can't have jackknifed we can't have jackknifed you can't have jackknifed they can't have jackknifed	I can't have been jackknifing you can't have been jackknifing he can't have been jackknifing we can't have been jackknifing you can't have been jackknifing they can't have been jackknifing

Interrogative form

Simple form	V-ing form
can I jackknife? can you jackknife? can he jackknife? can we jackknife? can you jackknife? can they jackknife?	can I be jackknifing? can you be jackknifing? can he be jackknifing? can we be jackknifing? can you be jackknifing? can they be jackknifing?
Perfect	V-ing perfect
can I have jackknifed? can you have jackknifed? can he have jackknifed? can we have jackknifed? can you have jackknifed? can they have jackknifed?	can I have been jackknifing? can you have been jackknifing? can he have been jackknifing? can we have been jackknifing? can you have been jackknifing? can they have been jackknifing?

Interro-negative form

Simple form	V-ing form
can't I jackknife? can't you jackknife? can't he jackknife? can't we jackknife? can't you jackknife? can't they jackknife?	can't I be jackknifing? can't you be jackknifing? can't he be jackknifing? can't we be jackknifing? can't you be jackknifing? can't they be jackknifing?
Perfect	V-ing perfect
can't I have jackknifed? can't you have jackknifed? can't he have jackknifed? can't we have jackknifed? can't you have jackknifed? can't they have jackknifed?	can't I have been jackknifing? can't you have been jackknifing? can't he have been jackknifing? can't we have been jackknifing? can't you have been jackknifing? can't they have been jackknifing?