English verb conjugation
MUST RETROFIT

Irregular verb: retrofit - retrofit - retrofit

Affirmation

Simple form	V-ing form
I must retrofit you must retrofit he must retrofit we must retrofit you must retrofit they must retrofit	I must be retrofiting you must be retrofiting he must be retrofiting we must be retrofiting you must be retrofiting they must be retrofiting
Perfect	V-ing perfect
I must have retrofit you must have retrofit he must have retrofit we must have retrofit you must have retrofit they must have retrofit	I must have been retrofiting you must have been retrofiting he must have been retrofiting we must have been retrofiting you must have been retrofiting they must have been retrofiting

Negation

Simple form	V-ing form
I must not retrofit you must not retrofit he must not retrofit we must not retrofit you must not retrofit they must not retrofit	I must not be retrofiting you must not be retrofiting he must not be retrofiting we must not be retrofiting you must not be retrofiting they must not be retrofiting
Perfect	V-ing perfect
I must not have retrofit you must not have retrofit he must not have retrofit we must not have retrofit you must not have retrofit they must not have retrofit	I must not have been retrofiting you must not have been retrofiting he must not have been retrofiting we must not have been retrofiting you must not have been retrofiting they must not have been retrofiting

Interrogative form

Simple form	V-ing form
must I retrofit? must you retrofit? must he retrofit? must we retrofit? must you retrofit? must they retrofit?	must I be retrofiting? must you be retrofiting? must he be retrofiting? must we be retrofiting? must you be retrofiting? must they be retrofiting?
Perfect	V-ing perfect
must I have retrofit? must you have retrofit? must he have retrofit? must we have retrofit? must you have retrofit? must they have retrofit?	must I have been retrofiting? must you have been retrofiting? must he have been retrofiting? must we have been retrofiting? must you have been retrofiting? must they have been retrofiting?

Interro-negative form

Simple form	V-ing form
must I not retrofit? must you not retrofit? must he not retrofit? must we not retrofit? must you not retrofit? must they not retrofit?	must I not be retrofiting? must you not be retrofiting? must he not be retrofiting? must we not be retrofiting? must you not be retrofiting? must they not be retrofiting?
Perfect	V-ing perfect
must I not have retrofit? must you not have retrofit? must he not have retrofit? must we not have retrofit? must you not have retrofit? must they not have retrofit?	must I not have been retrofiting? must you not have been retrofiting? must he not have been retrofiting? must we not have been retrofiting? must you not have been retrofiting? must they not have been retrofiting?