English verb conjugation
COULD RUIN

Regular verb: ruin - ruined - ruined

Affirmation

Simple form	V-ing form
I could ruin you could ruin she could ruin we could ruin you could ruin they could ruin	I could be ruining you could be ruining she could be ruining we could be ruining you could be ruining they could be ruining
Perfect	V-ing perfect
I could have ruined you could have ruined she could have ruined we could have ruined you could have ruined they could have ruined	I could have been ruining you could have been ruining she could have been ruining we could have been ruining you could have been ruining they could have been ruining

Negation

Simple form	V-ing form
I couldn't ruin you couldn't ruin she couldn't ruin we couldn't ruin you couldn't ruin they couldn't ruin	I couldn't be ruining you couldn't be ruining she couldn't be ruining we couldn't be ruining you couldn't be ruining they couldn't be ruining
Perfect	V-ing perfect
I couldn't have ruined you couldn't have ruined she couldn't have ruined we couldn't have ruined you couldn't have ruined they couldn't have ruined	I couldn't have been ruining you couldn't have been ruining she couldn't have been ruining we couldn't have been ruining you couldn't have been ruining they couldn't have been ruining

Interrogative form

Simple form	V-ing form
could I ruin? could you ruin? could she ruin? could we ruin? could you ruin? could they ruin?	could I be ruining? could you be ruining? could she be ruining? could we be ruining? could you be ruining? could they be ruining?
Perfect	V-ing perfect
could I have ruined? could you have ruined? could she have ruined? could we have ruined? could you have ruined? could they have ruined?	could I have been ruining? could you have been ruining? could she have been ruining? could we have been ruining? could you have been ruining? could they have been ruining?

Interro-negative form

Simple form	V-ing form
couldn't I ruin? couldn't you ruin? couldn't she ruin? couldn't we ruin? couldn't you ruin? couldn't they ruin?	couldn't I be ruining? couldn't you be ruining? couldn't she be ruining? couldn't we be ruining? couldn't you be ruining? couldn't they be ruining?
Perfect	V-ing perfect
couldn't I have ruined? couldn't you have ruined? couldn't she have ruined? couldn't we have ruined? couldn't you have ruined? couldn't they have ruined?	couldn't I have been ruining? couldn't you have been ruining? couldn't she have been ruining? couldn't we have been ruining? couldn't you have been ruining? couldn't they have been ruining?