English verb conjugation
MUST GRASS

Regular verb: grass - grassed - grassed

Affirmation

Simple form	V-ing form
I must grass you must grass he must grass we must grass you must grass they must grass	I must be grassing you must be grassing he must be grassing we must be grassing you must be grassing they must be grassing
Perfect	V-ing perfect
I must have grassed you must have grassed he must have grassed we must have grassed you must have grassed they must have grassed	I must have been grassing you must have been grassing he must have been grassing we must have been grassing you must have been grassing they must have been grassing

Negation

Simple form	V-ing form
I mustn't grass you mustn't grass he mustn't grass we mustn't grass you mustn't grass they mustn't grass	I mustn't be grassing you mustn't be grassing he mustn't be grassing we mustn't be grassing you mustn't be grassing they mustn't be grassing
Perfect	V-ing perfect
I mustn't have grassed you mustn't have grassed he mustn't have grassed we mustn't have grassed you mustn't have grassed they mustn't have grassed	I mustn't have been grassing you mustn't have been grassing he mustn't have been grassing we mustn't have been grassing you mustn't have been grassing they mustn't have been grassing

Interrogative form

Simple form	V-ing form
must I grass? must you grass? must he grass? must we grass? must you grass? must they grass?	must I be grassing? must you be grassing? must he be grassing? must we be grassing? must you be grassing? must they be grassing?
Perfect	V-ing perfect
must I have grassed? must you have grassed? must he have grassed? must we have grassed? must you have grassed? must they have grassed?	must I have been grassing? must you have been grassing? must he have been grassing? must we have been grassing? must you have been grassing? must they have been grassing?

Interro-negative form

Simple form	V-ing form
mustn't I grass? mustn't you grass? mustn't he grass? mustn't we grass? mustn't you grass? mustn't they grass?	mustn't I be grassing? mustn't you be grassing? mustn't he be grassing? mustn't we be grassing? mustn't you be grassing? mustn't they be grassing?
Perfect	V-ing perfect
mustn't I have grassed? mustn't you have grassed? mustn't he have grassed? mustn't we have grassed? mustn't you have grassed? mustn't they have grassed?	mustn't I have been grassing? mustn't you have been grassing? mustn't he have been grassing? mustn't we have been grassing? mustn't you have been grassing? mustn't they have been grassing?