may jackknife
Regular verb: jackknife - jackknifed- jackknifed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may jackknife
you may jackknife
she may jackknife
we may jackknife
you may jackknife
they may jackknife 	I may be jackknifing
you may be jackknifing
she may be jackknifing
we may be jackknifing
you may be jackknifing
they may be jackknifing	I may have jackknifed
you may have jackknifed
she may have jackknifed
we may have jackknifed
you may have jackknifed
they may have jackknifed	I may have been jackknifing
you may have been jackknifing
she may have been jackknifing
we may have been jackknifing
you may have been jackknifing
they may have been jackknifing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may not jackknife
you may not jackknife
she may not jackknife
we may not jackknife
you may not jackknife
they may not jackknife 	I may not be jackknifing
you may not be jackknifing
she may not be jackknifing
we may not be jackknifing
you may not be jackknifing
they may not be jackknifing	I may not have jackknifed
you may not have jackknifed
she may not have jackknifed
we may not have jackknifed
you may not have jackknifed
they may not have jackknifed	I may not have been jackknifing
you may not have been jackknifing
she may not have been jackknifing
we may not have been jackknifing
you may not have been jackknifing
they may not have been jackknifing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I jackknife?
may you jackknife?
may she jackknife?
may we jackknife?
may you jackknife?
may they jackknife? 	may I be jackknifing?
may you be jackknifing?
may she be jackknifing?
may we be jackknifing?
may you be jackknifing?
may they be jackknifing? 	may I have jackknifed?
may you have jackknifed?
may she have jackknifed?
may we have jackknifed?
may you have jackknifed?
may they have jackknifed? 	may I have been jackknifing?
may you have been jackknifing?
may she have been jackknifing?
may we have been jackknifing?
may you have been jackknifing?
may they have been jackknifing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I not jackknife?
may you not jackknife?
may she not jackknife?
may we not jackknife?
may you not jackknife?
may they not jackknife? 	may I not be jackknifing?
may you not be jackknifing?
may she not be jackknifing?
may we not be jackknifing?
may you not be jackknifing?
may they not be jackknifing? 	may I not have jackknifed?
may you not have jackknifed?
may she not have jackknifed?
may we not have jackknifed?
may you not have jackknifed?
may they not have jackknifed? 	may I not have been jackknifing?
may you not have been jackknifing?
may she not have been jackknifing?
may we not have been jackknifing?
may you not have been jackknifing?
may they not have been jackknifing?