English verb conjugation
MUST RUIN

Regular verb: ruin - ruined - ruined

Affirmation

Simple form	V-ing form
I must ruin you must ruin he must ruin we must ruin you must ruin they must ruin	I must be ruining you must be ruining he 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 he 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 he 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 mustn't ruin you mustn't ruin he mustn't ruin we mustn't ruin you mustn't ruin they mustn't ruin	I mustn't be ruining you mustn't be ruining he mustn't be ruining we mustn't be ruining you mustn't be ruining they mustn't be ruining
Perfect	V-ing perfect
I mustn't have ruined you mustn't have ruined he mustn't have ruined we mustn't have ruined you mustn't have ruined they mustn't have ruined	I mustn't have been ruining you mustn't have been ruining he mustn't have been ruining we mustn't have been ruining you mustn't have been ruining they mustn't have been ruining

Interrogative form

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