English verb conjugation
MUST COUNTERVAIL

Regular verb: countervail - countervailed - countervailed

Affirmation

Simple form	V-ing form
I must countervail you must countervail he must countervail we must countervail you must countervail they must countervail	I must be countervailing you must be countervailing he must be countervailing we must be countervailing you must be countervailing they must be countervailing
Perfect	V-ing perfect
I must have countervailed you must have countervailed he must have countervailed we must have countervailed you must have countervailed they must have countervailed	I must have been countervailing you must have been countervailing he must have been countervailing we must have been countervailing you must have been countervailing they must have been countervailing

Negation

Simple form	V-ing form
I mustn't countervail you mustn't countervail he mustn't countervail we mustn't countervail you mustn't countervail they mustn't countervail	I mustn't be countervailing you mustn't be countervailing he mustn't be countervailing we mustn't be countervailing you mustn't be countervailing they mustn't be countervailing
Perfect	V-ing perfect
I mustn't have countervailed you mustn't have countervailed he mustn't have countervailed we mustn't have countervailed you mustn't have countervailed they mustn't have countervailed	I mustn't have been countervailing you mustn't have been countervailing he mustn't have been countervailing we mustn't have been countervailing you mustn't have been countervailing they mustn't have been countervailing

Interrogative form

Simple form	V-ing form
must I countervail? must you countervail? must he countervail? must we countervail? must you countervail? must they countervail?	must I be countervailing? must you be countervailing? must he be countervailing? must we be countervailing? must you be countervailing? must they be countervailing?
Perfect	V-ing perfect
must I have countervailed? must you have countervailed? must he have countervailed? must we have countervailed? must you have countervailed? must they have countervailed?	must I have been countervailing? must you have been countervailing? must he have been countervailing? must we have been countervailing? must you have been countervailing? must they have been countervailing?

Interro-negative form

Simple form	V-ing form
mustn't I countervail? mustn't you countervail? mustn't he countervail? mustn't we countervail? mustn't you countervail? mustn't they countervail?	mustn't I be countervailing? mustn't you be countervailing? mustn't he be countervailing? mustn't we be countervailing? mustn't you be countervailing? mustn't they be countervailing?
Perfect	V-ing perfect
mustn't I have countervailed? mustn't you have countervailed? mustn't he have countervailed? mustn't we have countervailed? mustn't you have countervailed? mustn't they have countervailed?	mustn't I have been countervailing? mustn't you have been countervailing? mustn't he have been countervailing? mustn't we have been countervailing? mustn't you have been countervailing? mustn't they have been countervailing?