English verb conjugation COULD STIFF

Regular verb: stiff - stiffed - stiffed

Affirmation

Simple form

I could stiff
you could stiff
he could stiff
we could stiff
you could stiff
they could stiff

V-ing form

I could be stiffing
you could be stiffing
he could be stiffing
we could be stiffing
you could be stiffing
they could be stiffing

Perfect

I could have stiffed
you could have stiffed
he could have stiffed
we could have stiffed
you could have stiffed
they could have stiffed

V-ing perfect

I could have been stiffing
you could have been stiffing
he could have been stiffing
we could have been stiffing
you could have been stiffing
they could have been stiffing

Negation

Simple form

I couldn't stiff
you couldn't stiff
he couldn't stiff
we couldn't stiff
you couldn't stiff
they couldn't stiff

V-ing form

I couldn't be stiffing
you couldn't be stiffing
he couldn't be stiffing
we couldn't be stiffing
you couldn't be stiffing
they couldn't be stiffing

Perfect

I couldn't have stiffed
you couldn't have stiffed
he couldn't have stiffed
we couldn't have stiffed
you couldn't have stiffed
they couldn't have stiffed

V-ing perfect

I couldn't have been stiffing
you couldn't have been stiffing
he couldn't have been stiffing
we couldn't have been stiffing
you couldn't have been stiffing
they couldn't have been stiffing

Interrogative form

Simple form

could I stiff?
could you stiff?
could he stiff?
could we stiff?
could you stiff?
could they stiff?

V-ing form

could I be stiffing?
could you be stiffing?
could he be stiffing?
could we be stiffing?
could you be stiffing?
could they be stiffing?

Perfect

could I have stiffed?
could you have stiffed?
could he have stiffed?
could we have stiffed?
could you have stiffed?
could they have stiffed?

V-ing perfect

could I have been stiffing?
could you have been stiffing?
could he have been stiffing?
could we have been stiffing?
could you have been stiffing?
could they have been stiffing?

Interro-negative form

Simple form

couldn't I stiff?
couldn't you stiff?
couldn't he stiff?
couldn't we stiff?
couldn't you stiff?
couldn't they stiff?

V-ing form

couldn't I be stiffing?
couldn't you be stiffing?
couldn't he be stiffing?
couldn't we be stiffing?
couldn't you be stiffing?
couldn't they be stiffing?

Perfect

couldn't I have stiffed?
couldn't you have stiffed?
couldn't he have stiffed?
couldn't we have stiffed?
couldn't you have stiffed?
couldn't they have stiffed?

V-ing perfect

couldn't I have been stiffing?
couldn't you have been stiffing?
couldn't he have been stiffing?
couldn't we have been stiffing?
couldn't you have been stiffing?
couldn't they have been stiffing?

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