English verb conjugation COULD SUM

Regular verb: sum - summed - summed

Affirmation

Simple form

I could sum
you could sum
he could sum
we could sum
you could sum
they could sum

V-ing form

I could be summing
you could be summing
he could be summing
we could be summing
you could be summing
they could be summing

Perfect

I could have summed
you could have summed
he could have summed
we could have summed
you could have summed
they could have summed

V-ing perfect

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

Negation

Simple form

I could not sum
you could not sum
he could not sum
we could not sum
you could not sum
they could not sum

V-ing form

I could not be summing
you could not be summing
he could not be summing
we could not be summing
you could not be summing
they could not be summing

Perfect

I could not have summed
you could not have summed
he could not have summed
we could not have summed
you could not have summed
they could not have summed

V-ing perfect

I could not have been summing
you could not have been summing
he could not have been summing
we could not have been summing
you could not have been summing
they could not have been summing

Interrogative form

Simple form

could I sum?
could you sum?
could he sum?
could we sum?
could you sum?
could they sum?

V-ing form

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

Perfect

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

V-ing perfect

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

Interro-negative form

Simple form

could I not sum?
could you not sum?
could he not sum?
could we not sum?
could you not sum?
could they not sum?

V-ing form

could I not be summing?
could you not be summing?
could he not be summing?
could we not be summing?
could you not be summing?
could they not be summing?

Perfect

could I not have summed?
could you not have summed?
could he not have summed?
could we not have summed?
could you not have summed?
could they not have summed?

V-ing perfect

could I not have been summing?
could you not have been summing?
could he not have been summing?
could we not have been summing?
could you not have been summing?
could they not have been summing?

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