English verb conjugation
CAN UNDERPIN

Regular verb: underpin - underpinned - underpinned

Affirmation

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

Negation

Simple form	V-ing form
I cannot underpin you cannot underpin he cannot underpin we cannot underpin you cannot underpin they cannot underpin	I cannot be underpinning you cannot be underpinning he cannot be underpinning we cannot be underpinning you cannot be underpinning they cannot be underpinning
Perfect	V-ing perfect
I cannot have underpinned you cannot have underpinned he cannot have underpinned we cannot have underpinned you cannot have underpinned they cannot have underpinned	I cannot have been underpinning you cannot have been underpinning he cannot have been underpinning we cannot have been underpinning you cannot have been underpinning they cannot have been underpinning

Interrogative form

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

Interro-negative form

Simple form	V-ing form
can I not underpin? can you not underpin? can he not underpin? can we not underpin? can you not underpin? can they not underpin?	can I not be underpinning? can you not be underpinning? can he not be underpinning? can we not be underpinning? can you not be underpinning? can they not be underpinning?
Perfect	V-ing perfect
can I not have underpinned? can you not have underpinned? can he not have underpinned? can we not have underpinned? can you not have underpinned? can they not have underpinned?	can I not have been underpinning? can you not have been underpinning? can he not have been underpinning? can we not have been underpinning? can you not have been underpinning? can they not have been underpinning?