English verb conjugation
OUGHT TO PREVENT

Regular verb: prevent - prevented - prevented

Affirmation

Simple form	V-ing form
I ought to prevent you ought to prevent he ought to prevent we ought to prevent you ought to prevent they ought to prevent	I ought to be preventing you ought to be preventing he ought to be preventing we ought to be preventing you ought to be preventing they ought to be preventing
Perfect	V-ing perfect
I ought to have prevented you ought to have prevented he ought to have prevented we ought to have prevented you ought to have prevented they ought to have prevented	I ought to have been preventing you ought to have been preventing he ought to have been preventing we ought to have been preventing you ought to have been preventing they ought to have been preventing

Negation

Simple form	V-ing form
I oughtn't to prevent you oughtn't to prevent he oughtn't to prevent we oughtn't to prevent you oughtn't to prevent they oughtn't to prevent	I oughtn't to be preventing you oughtn't to be preventing he oughtn't to be preventing we oughtn't to be preventing you oughtn't to be preventing they oughtn't to be preventing
Perfect	V-ing perfect
I oughtn't to have prevented you oughtn't to have prevented he oughtn't to have prevented we oughtn't to have prevented you oughtn't to have prevented they oughtn't to have prevented	I oughtn't to have been preventing you oughtn't to have been preventing he oughtn't to have been preventing we oughtn't to have been preventing you oughtn't to have been preventing they oughtn't to have been preventing

Interrogative form

Simple form	V-ing form
ought to I prevent? ought to you prevent? ought to he prevent? ought to we prevent? ought to you prevent? ought to they prevent?	ought to I be preventing? ought to you be preventing? ought to he be preventing? ought to we be preventing? ought to you be preventing? ought to they be preventing?
Perfect	V-ing perfect
ought to I have prevented? ought to you have prevented? ought to he have prevented? ought to we have prevented? ought to you have prevented? ought to they have prevented?	ought to I have been preventing? ought to you have been preventing? ought to he have been preventing? ought to we have been preventing? ought to you have been preventing? ought to they have been preventing?

Interro-negative form

Simple form	V-ing form
oughtn't I to prevent? oughtn't you to prevent? oughtn't he to prevent? oughtn't we to prevent? oughtn't you to prevent? oughtn't they to prevent?	oughtn't I to be preventing? oughtn't you to be preventing? oughtn't he to be preventing? oughtn't we to be preventing? oughtn't you to be preventing? oughtn't they to be preventing?
Perfect	V-ing perfect
oughtn't I to have prevented? oughtn't you to have prevented? oughtn't he to have prevented? oughtn't we to have prevented? oughtn't you to have prevented? oughtn't they to have prevented?	oughtn't I to have been preventing? oughtn't you to have been preventing? oughtn't he to have been preventing? oughtn't we to have been preventing? oughtn't you to have been preventing? oughtn't they to have been preventing?