must underpay
Irregular verb: underpay - underpaid- underpaid

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must underpay
you must underpay
she must underpay
we must underpay
you must underpay
they must underpay 	I must be underpaying
you must be underpaying
she must be underpaying
we must be underpaying
you must be underpaying
they must be underpaying	I must have underpaid
you must have underpaid
she must have underpaid
we must have underpaid
you must have underpaid
they must have underpaid	I must have been underpaying
you must have been underpaying
she must have been underpaying
we must have been underpaying
you must have been underpaying
they must have been underpaying	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not underpay
you must not underpay
she must not underpay
we must not underpay
you must not underpay
they must not underpay 	I must not be underpaying
you must not be underpaying
she must not be underpaying
we must not be underpaying
you must not be underpaying
they must not be underpaying	I must not have underpaid
you must not have underpaid
she must not have underpaid
we must not have underpaid
you must not have underpaid
they must not have underpaid	I must not have been underpaying
you must not have been underpaying
she must not have been underpaying
we must not have been underpaying
you must not have been underpaying
they must not have been underpaying	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I underpay?
must you underpay?
must she underpay?
must we underpay?
must you underpay?
must they underpay? 	must I be underpaying?
must you be underpaying?
must she be underpaying?
must we be underpaying?
must you be underpaying?
must they be underpaying? 	must I have underpaid?
must you have underpaid?
must she have underpaid?
must we have underpaid?
must you have underpaid?
must they have underpaid? 	must I have been underpaying?
must you have been underpaying?
must she have been underpaying?
must we have been underpaying?
must you have been underpaying?
must they have been underpaying? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not underpay?
must you not underpay?
must she not underpay?
must we not underpay?
must you not underpay?
must they not underpay? 	must I not be underpaying?
must you not be underpaying?
must she not be underpaying?
must we not be underpaying?
must you not be underpaying?
must they not be underpaying? 	must I not have underpaid?
must you not have underpaid?
must she not have underpaid?
must we not have underpaid?
must you not have underpaid?
must they not have underpaid? 	must I not have been underpaying?
must you not have been underpaying?
must she not have been underpaying?
must we not have been underpaying?
must you not have been underpaying?
must they not have been underpaying?