English verb conjugation COULD ALTER

Regular verb: alter - altered - altered


Affirmation

Simple form

I could alter
you could alter
he could alter
we could alter
you could alter
they could alter

V-ing form

I could be altering
you could be altering
he could be altering
we could be altering
you could be altering
they could be altering

Perfect

I could have altered
you could have altered
he could have altered
we could have altered
you could have altered
they could have altered

V-ing perfect

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

Negation

Simple form

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

V-ing form

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

Perfect

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

V-ing perfect

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

Interrogative form

Simple form

could I alter?
could you alter?
could he alter?
could we alter?
could you alter?
could they alter?

V-ing form

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

Perfect

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

V-ing perfect

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

Interro-negative form

Simple form

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

V-ing form

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

Perfect

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

V-ing perfect

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