must steepen
Regular verb: steepen - steepened- steepened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must steepen
you must steepen
she must steepen
we must steepen
you must steepen
they must steepen 	I must be steepening
you must be steepening
she must be steepening
we must be steepening
you must be steepening
they must be steepening	I must have steepened
you must have steepened
she must have steepened
we must have steepened
you must have steepened
they must have steepened	I must have been steepening
you must have been steepening
she must have been steepening
we must have been steepening
you must have been steepening
they must have been steepening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not steepen
you must not steepen
she must not steepen
we must not steepen
you must not steepen
they must not steepen 	I must not be steepening
you must not be steepening
she must not be steepening
we must not be steepening
you must not be steepening
they must not be steepening	I must not have steepened
you must not have steepened
she must not have steepened
we must not have steepened
you must not have steepened
they must not have steepened	I must not have been steepening
you must not have been steepening
she must not have been steepening
we must not have been steepening
you must not have been steepening
they must not have been steepening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I steepen?
must you steepen?
must she steepen?
must we steepen?
must you steepen?
must they steepen? 	must I be steepening?
must you be steepening?
must she be steepening?
must we be steepening?
must you be steepening?
must they be steepening? 	must I have steepened?
must you have steepened?
must she have steepened?
must we have steepened?
must you have steepened?
must they have steepened? 	must I have been steepening?
must you have been steepening?
must she have been steepening?
must we have been steepening?
must you have been steepening?
must they have been steepening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not steepen?
must you not steepen?
must she not steepen?
must we not steepen?
must you not steepen?
must they not steepen? 	must I not be steepening?
must you not be steepening?
must she not be steepening?
must we not be steepening?
must you not be steepening?
must they not be steepening? 	must I not have steepened?
must you not have steepened?
must she not have steepened?
must we not have steepened?
must you not have steepened?
must they not have steepened? 	must I not have been steepening?
must you not have been steepening?
must she not have been steepening?
must we not have been steepening?
must you not have been steepening?
must they not have been steepening?