English verb conjugation
CAN INVESTIGATE

Regular verb: investigate - investigated - investigated

Affirmation

Simple form	V-ing form
I can investigate you can investigate he can investigate we can investigate you can investigate they can investigate	I can be investigating you can be investigating he can be investigating we can be investigating you can be investigating they can be investigating
Perfect	V-ing perfect
I can have investigated you can have investigated he can have investigated we can have investigated you can have investigated they can have investigated	I can have been investigating you can have been investigating he can have been investigating we can have been investigating you can have been investigating they can have been investigating

Negation

Simple form	V-ing form
I can't investigate you can't investigate he can't investigate we can't investigate you can't investigate they can't investigate	I can't be investigating you can't be investigating he can't be investigating we can't be investigating you can't be investigating they can't be investigating
Perfect	V-ing perfect
I can't have investigated you can't have investigated he can't have investigated we can't have investigated you can't have investigated they can't have investigated	I can't have been investigating you can't have been investigating he can't have been investigating we can't have been investigating you can't have been investigating they can't have been investigating

Interrogative form

Simple form	V-ing form
can I investigate? can you investigate? can he investigate? can we investigate? can you investigate? can they investigate?	can I be investigating? can you be investigating? can he be investigating? can we be investigating? can you be investigating? can they be investigating?
Perfect	V-ing perfect
can I have investigated? can you have investigated? can he have investigated? can we have investigated? can you have investigated? can they have investigated?	can I have been investigating? can you have been investigating? can he have been investigating? can we have been investigating? can you have been investigating? can they have been investigating?

Interro-negative form

Simple form	V-ing form
can't I investigate? can't you investigate? can't he investigate? can't we investigate? can't you investigate? can't they investigate?	can't I be investigating? can't you be investigating? can't he be investigating? can't we be investigating? can't you be investigating? can't they be investigating?
Perfect	V-ing perfect
can't I have investigated? can't you have investigated? can't he have investigated? can't we have investigated? can't you have investigated? can't they have investigated?	can't I have been investigating? can't you have been investigating? can't he have been investigating? can't we have been investigating? can't you have been investigating? can't they have been investigating?