English verb conjugation
MUST TOUGH

Regular verb: tough - toughed - toughed

Affirmation

Simple form	V-ing form
I must tough you must tough he must tough we must tough you must tough they must tough	I must be toughing you must be toughing he must be toughing we must be toughing you must be toughing they must be toughing
Perfect	V-ing perfect
I must have toughed you must have toughed he must have toughed we must have toughed you must have toughed they must have toughed	I must have been toughing you must have been toughing he must have been toughing we must have been toughing you must have been toughing they must have been toughing

Negation

Simple form	V-ing form
I mustn't tough you mustn't tough he mustn't tough we mustn't tough you mustn't tough they mustn't tough	I mustn't be toughing you mustn't be toughing he mustn't be toughing we mustn't be toughing you mustn't be toughing they mustn't be toughing
Perfect	V-ing perfect
I mustn't have toughed you mustn't have toughed he mustn't have toughed we mustn't have toughed you mustn't have toughed they mustn't have toughed	I mustn't have been toughing you mustn't have been toughing he mustn't have been toughing we mustn't have been toughing you mustn't have been toughing they mustn't have been toughing

Interrogative form

Simple form	V-ing form
must I tough? must you tough? must he tough? must we tough? must you tough? must they tough?	must I be toughing? must you be toughing? must he be toughing? must we be toughing? must you be toughing? must they be toughing?
Perfect	V-ing perfect
must I have toughed? must you have toughed? must he have toughed? must we have toughed? must you have toughed? must they have toughed?	must I have been toughing? must you have been toughing? must he have been toughing? must we have been toughing? must you have been toughing? must they have been toughing?

Interro-negative form

Simple form	V-ing form
mustn't I tough? mustn't you tough? mustn't he tough? mustn't we tough? mustn't you tough? mustn't they tough?	mustn't I be toughing? mustn't you be toughing? mustn't he be toughing? mustn't we be toughing? mustn't you be toughing? mustn't they be toughing?
Perfect	V-ing perfect
mustn't I have toughed? mustn't you have toughed? mustn't he have toughed? mustn't we have toughed? mustn't you have toughed? mustn't they have toughed?	mustn't I have been toughing? mustn't you have been toughing? mustn't he have been toughing? mustn't we have been toughing? mustn't you have been toughing? mustn't they have been toughing?