may preinvestigate
Regular verb: preinvestigate - preinvestigated- preinvestigated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may preinvestigate
you may preinvestigate
he may preinvestigate
we may preinvestigate
you may preinvestigate
they may preinvestigate 	I may be preinvestigating
you may be preinvestigating
he may be preinvestigating
we may be preinvestigating
you may be preinvestigating
they may be preinvestigating	I may have preinvestigated
you may have preinvestigated
he may have preinvestigated
we may have preinvestigated
you may have preinvestigated
they may have preinvestigated	I may have been preinvestigating
you may have been preinvestigating
he may have been preinvestigating
we may have been preinvestigating
you may have been preinvestigating
they may have been preinvestigating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mayn't preinvestigate
you mayn't preinvestigate
he mayn't preinvestigate
we mayn't preinvestigate
you mayn't preinvestigate
they mayn't preinvestigate 	I mayn't be preinvestigating
you mayn't be preinvestigating
he mayn't be preinvestigating
we mayn't be preinvestigating
you mayn't be preinvestigating
they mayn't be preinvestigating	I mayn't have preinvestigated
you mayn't have preinvestigated
he mayn't have preinvestigated
we mayn't have preinvestigated
you mayn't have preinvestigated
they mayn't have preinvestigated	I mayn't have been preinvestigating
you mayn't have been preinvestigating
he mayn't have been preinvestigating
we mayn't have been preinvestigating
you mayn't have been preinvestigating
they mayn't have been preinvestigating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I preinvestigate?
may you preinvestigate?
may he preinvestigate?
may we preinvestigate?
may you preinvestigate?
may they preinvestigate? 	may I be preinvestigating?
may you be preinvestigating?
may he be preinvestigating?
may we be preinvestigating?
may you be preinvestigating?
may they be preinvestigating? 	may I have preinvestigated?
may you have preinvestigated?
may he have preinvestigated?
may we have preinvestigated?
may you have preinvestigated?
may they have preinvestigated? 	may I have been preinvestigating?
may you have been preinvestigating?
may he have been preinvestigating?
may we have been preinvestigating?
may you have been preinvestigating?
may they have been preinvestigating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mayn't I preinvestigate?
mayn't you preinvestigate?
mayn't he preinvestigate?
mayn't we preinvestigate?
mayn't you preinvestigate?
mayn't they preinvestigate? 	mayn't I be preinvestigating?
mayn't you be preinvestigating?
mayn't he be preinvestigating?
mayn't we be preinvestigating?
mayn't you be preinvestigating?
mayn't they be preinvestigating? 	mayn't I have preinvestigated?
mayn't you have preinvestigated?
mayn't he have preinvestigated?
mayn't we have preinvestigated?
mayn't you have preinvestigated?
mayn't they have preinvestigated? 	mayn't I have been preinvestigating?
mayn't you have been preinvestigating?
mayn't he have been preinvestigating?
mayn't we have been preinvestigating?
mayn't you have been preinvestigating?
mayn't they have been preinvestigating?