English verb conjugation
MUST GAS

Regular verb: gas - gassed - gassed

Affirmation

Simple form	V-ing form
I must gas you must gas he must gas we must gas you must gas they must gas	I must be gassing you must be gassing he must be gassing we must be gassing you must be gassing they must be gassing
Perfect	V-ing perfect
I must have gassed you must have gassed he must have gassed we must have gassed you must have gassed they must have gassed	I must have been gassing you must have been gassing he must have been gassing we must have been gassing you must have been gassing they must have been gassing

Negation

Simple form	V-ing form
I mustn't gas you mustn't gas he mustn't gas we mustn't gas you mustn't gas they mustn't gas	I mustn't be gassing you mustn't be gassing he mustn't be gassing we mustn't be gassing you mustn't be gassing they mustn't be gassing
Perfect	V-ing perfect
I mustn't have gassed you mustn't have gassed he mustn't have gassed we mustn't have gassed you mustn't have gassed they mustn't have gassed	I mustn't have been gassing you mustn't have been gassing he mustn't have been gassing we mustn't have been gassing you mustn't have been gassing they mustn't have been gassing

Interrogative form

Simple form	V-ing form
must I gas? must you gas? must he gas? must we gas? must you gas? must they gas?	must I be gassing? must you be gassing? must he be gassing? must we be gassing? must you be gassing? must they be gassing?
Perfect	V-ing perfect
must I have gassed? must you have gassed? must he have gassed? must we have gassed? must you have gassed? must they have gassed?	must I have been gassing? must you have been gassing? must he have been gassing? must we have been gassing? must you have been gassing? must they have been gassing?

Interro-negative form

Simple form	V-ing form
mustn't I gas? mustn't you gas? mustn't he gas? mustn't we gas? mustn't you gas? mustn't they gas?	mustn't I be gassing? mustn't you be gassing? mustn't he be gassing? mustn't we be gassing? mustn't you be gassing? mustn't they be gassing?
Perfect	V-ing perfect
mustn't I have gassed? mustn't you have gassed? mustn't he have gassed? mustn't we have gassed? mustn't you have gassed? mustn't they have gassed?	mustn't I have been gassing? mustn't you have been gassing? mustn't he have been gassing? mustn't we have been gassing? mustn't you have been gassing? mustn't they have been gassing?