English verb conjugation
MUST RUIN

Regular verb: ruin - ruined - ruined

Affirmation

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

Negation

Simple form	V-ing form
I must not ruin you must not ruin she must not ruin we must not ruin you must not ruin they must not ruin	I must not be ruining you must not be ruining she must not be ruining we must not be ruining you must not be ruining they must not be ruining
Perfect	V-ing perfect
I must not have ruined you must not have ruined she must not have ruined we must not have ruined you must not have ruined they must not have ruined	I must not have been ruining you must not have been ruining she must not have been ruining we must not have been ruining you must not have been ruining they must not have been ruining

Interrogative form

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

Interro-negative form

Simple form	V-ing form
must I not ruin? must you not ruin? must she not ruin? must we not ruin? must you not ruin? must they not ruin?	must I not be ruining? must you not be ruining? must she not be ruining? must we not be ruining? must you not be ruining? must they not be ruining?
Perfect	V-ing perfect
must I not have ruined? must you not have ruined? must she not have ruined? must we not have ruined? must you not have ruined? must they not have ruined?	must I not have been ruining? must you not have been ruining? must she not have been ruining? must we not have been ruining? must you not have been ruining? must they not have been ruining?