may investigate
Regular verb: investigate - investigated- investigated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may investigate
you may investigate
she may investigate
we may investigate
you may investigate
they may investigate 	I may be investigating
you may be investigating
she may be investigating
we may be investigating
you may be investigating
they may be investigating	I may have investigated
you may have investigated
she may have investigated
we may have investigated
you may have investigated
they may have investigated	I may have been investigating
you may have been investigating
she may have been investigating
we may have been investigating
you may have been investigating
they may have been investigating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mayn't investigate
you mayn't investigate
she mayn't investigate
we mayn't investigate
you mayn't investigate
they mayn't investigate 	I mayn't be investigating
you mayn't be investigating
she mayn't be investigating
we mayn't be investigating
you mayn't be investigating
they mayn't be investigating	I mayn't have investigated
you mayn't have investigated
she mayn't have investigated
we mayn't have investigated
you mayn't have investigated
they mayn't have investigated	I mayn't have been investigating
you mayn't have been investigating
she mayn't have been investigating
we mayn't have been investigating
you mayn't have been investigating
they mayn't have been investigating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I investigate?
may you investigate?
may she investigate?
may we investigate?
may you investigate?
may they investigate? 	may I be investigating?
may you be investigating?
may she be investigating?
may we be investigating?
may you be investigating?
may they be investigating? 	may I have investigated?
may you have investigated?
may she have investigated?
may we have investigated?
may you have investigated?
may they have investigated? 	may I have been investigating?
may you have been investigating?
may she have been investigating?
may we have been investigating?
may you have been investigating?
may they have been investigating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mayn't I investigate?
mayn't you investigate?
mayn't she investigate?
mayn't we investigate?
mayn't you investigate?
mayn't they investigate? 	mayn't I be investigating?
mayn't you be investigating?
mayn't she be investigating?
mayn't we be investigating?
mayn't you be investigating?
mayn't they be investigating? 	mayn't I have investigated?
mayn't you have investigated?
mayn't she have investigated?
mayn't we have investigated?
mayn't you have investigated?
mayn't they have investigated? 	mayn't I have been investigating?
mayn't you have been investigating?
mayn't she have been investigating?
mayn't we have been investigating?
mayn't you have been investigating?
mayn't they have been investigating?