must preinvestigate
Verbo regular: preinvestigate - preinvestigated- preinvestigated

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must preinvestigate
you must preinvestigate
he must preinvestigate
we must preinvestigate
you must preinvestigate
they must preinvestigate 	I must be preinvestigating
you must be preinvestigating
he must be preinvestigating
we must be preinvestigating
you must be preinvestigating
they must be preinvestigating	I must have preinvestigated
you must have preinvestigated
he must have preinvestigated
we must have preinvestigated
you must have preinvestigated
they must have preinvestigated	I must have been preinvestigating
you must have been preinvestigating
he must have been preinvestigating
we must have been preinvestigating
you must have been preinvestigating
they must have been preinvestigating	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not preinvestigate
you must not preinvestigate
he must not preinvestigate
we must not preinvestigate
you must not preinvestigate
they must not preinvestigate 	I must not be preinvestigating
you must not be preinvestigating
he must not be preinvestigating
we must not be preinvestigating
you must not be preinvestigating
they must not be preinvestigating	I must not have preinvestigated
you must not have preinvestigated
he must not have preinvestigated
we must not have preinvestigated
you must not have preinvestigated
they must not have preinvestigated	I must not have been preinvestigating
you must not have been preinvestigating
he must not have been preinvestigating
we must not have been preinvestigating
you must not have been preinvestigating
they must not have been preinvestigating	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I preinvestigate?
must you preinvestigate?
must he preinvestigate?
must we preinvestigate?
must you preinvestigate?
must they preinvestigate? 	must I be preinvestigating?
must you be preinvestigating?
must he be preinvestigating?
must we be preinvestigating?
must you be preinvestigating?
must they be preinvestigating? 	must I have preinvestigated?
must you have preinvestigated?
must he have preinvestigated?
must we have preinvestigated?
must you have preinvestigated?
must they have preinvestigated? 	must I have been preinvestigating?
must you have been preinvestigating?
must he have been preinvestigating?
must we have been preinvestigating?
must you have been preinvestigating?
must they have been preinvestigating? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not preinvestigate?
must you not preinvestigate?
must he not preinvestigate?
must we not preinvestigate?
must you not preinvestigate?
must they not preinvestigate? 	must I not be preinvestigating?
must you not be preinvestigating?
must he not be preinvestigating?
must we not be preinvestigating?
must you not be preinvestigating?
must they not be preinvestigating? 	must I not have preinvestigated?
must you not have preinvestigated?
must he not have preinvestigated?
must we not have preinvestigated?
must you not have preinvestigated?
must they not have preinvestigated? 	must I not have been preinvestigating?
must you not have been preinvestigating?
must he not have been preinvestigating?
must we not have been preinvestigating?
must you not have been preinvestigating?
must they not have been preinvestigating?