could investigate
Verbo regular: investigate - investigated- investigated

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could investigate
you could investigate
she could investigate
we could investigate
you could investigate
they could investigate 	I could be investigating
you could be investigating
she could be investigating
we could be investigating
you could be investigating
they could be investigating	I could have investigated
you could have investigated
she could have investigated
we could have investigated
you could have investigated
they could have investigated	I could have been investigating
you could have been investigating
she could have been investigating
we could have been investigating
you could have been investigating
they could have been investigating	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not investigate
you could not investigate
she could not investigate
we could not investigate
you could not investigate
they could not investigate 	I could not be investigating
you could not be investigating
she could not be investigating
we could not be investigating
you could not be investigating
they could not be investigating	I could not have investigated
you could not have investigated
she could not have investigated
we could not have investigated
you could not have investigated
they could not have investigated	I could not have been investigating
you could not have been investigating
she could not have been investigating
we could not have been investigating
you could not have been investigating
they could not have been investigating	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I investigate?
could you investigate?
could she investigate?
could we investigate?
could you investigate?
could they investigate? 	could I be investigating?
could you be investigating?
could she be investigating?
could we be investigating?
could you be investigating?
could they be investigating? 	could I have investigated?
could you have investigated?
could she have investigated?
could we have investigated?
could you have investigated?
could they have investigated? 	could I have been investigating?
could you have been investigating?
could she have been investigating?
could we have been investigating?
could you have been investigating?
could they have been investigating? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not investigate?
could you not investigate?
could she not investigate?
could we not investigate?
could you not investigate?
could they not investigate? 	could I not be investigating?
could you not be investigating?
could she not be investigating?
could we not be investigating?
could you not be investigating?
could they not be investigating? 	could I not have investigated?
could you not have investigated?
could she not have investigated?
could we not have investigated?
could you not have investigated?
could they not have investigated? 	could I not have been investigating?
could you not have been investigating?
could she not have been investigating?
could we not have been investigating?
could you not have been investigating?
could they not have been investigating?