may underpin
Regular verb: underpin - underpinned- underpinned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may underpin
you may underpin
he may underpin
we may underpin
you may underpin
they may underpin 	I may be underpinning
you may be underpinning
he may be underpinning
we may be underpinning
you may be underpinning
they may be underpinning	I may have underpinned
you may have underpinned
he may have underpinned
we may have underpinned
you may have underpinned
they may have underpinned	I may have been underpinning
you may have been underpinning
he may have been underpinning
we may have been underpinning
you may have been underpinning
they may have been underpinning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mayn't underpin
you mayn't underpin
he mayn't underpin
we mayn't underpin
you mayn't underpin
they mayn't underpin 	I mayn't be underpinning
you mayn't be underpinning
he mayn't be underpinning
we mayn't be underpinning
you mayn't be underpinning
they mayn't be underpinning	I mayn't have underpinned
you mayn't have underpinned
he mayn't have underpinned
we mayn't have underpinned
you mayn't have underpinned
they mayn't have underpinned	I mayn't have been underpinning
you mayn't have been underpinning
he mayn't have been underpinning
we mayn't have been underpinning
you mayn't have been underpinning
they mayn't have been underpinning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I underpin?
may you underpin?
may he underpin?
may we underpin?
may you underpin?
may they underpin? 	may I be underpinning?
may you be underpinning?
may he be underpinning?
may we be underpinning?
may you be underpinning?
may they be underpinning? 	may I have underpinned?
may you have underpinned?
may he have underpinned?
may we have underpinned?
may you have underpinned?
may they have underpinned? 	may I have been underpinning?
may you have been underpinning?
may he have been underpinning?
may we have been underpinning?
may you have been underpinning?
may they have been underpinning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mayn't I underpin?
mayn't you underpin?
mayn't he underpin?
mayn't we underpin?
mayn't you underpin?
mayn't they underpin? 	mayn't I be underpinning?
mayn't you be underpinning?
mayn't he be underpinning?
mayn't we be underpinning?
mayn't you be underpinning?
mayn't they be underpinning? 	mayn't I have underpinned?
mayn't you have underpinned?
mayn't he have underpinned?
mayn't we have underpinned?
mayn't you have underpinned?
mayn't they have underpinned? 	mayn't I have been underpinning?
mayn't you have been underpinning?
mayn't he have been underpinning?
mayn't we have been underpinning?
mayn't you have been underpinning?
mayn't they have been underpinning?