could penetrate
Regular verb: penetrate - penetrated- penetrated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could penetrate
you could penetrate
he could penetrate
we could penetrate
you could penetrate
they could penetrate 	I could be penetrating
you could be penetrating
he could be penetrating
we could be penetrating
you could be penetrating
they could be penetrating	I could have penetrated
you could have penetrated
he could have penetrated
we could have penetrated
you could have penetrated
they could have penetrated	I could have been penetrating
you could have been penetrating
he could have been penetrating
we could have been penetrating
you could have been penetrating
they could have been penetrating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not penetrate
you could not penetrate
he could not penetrate
we could not penetrate
you could not penetrate
they could not penetrate 	I could not be penetrating
you could not be penetrating
he could not be penetrating
we could not be penetrating
you could not be penetrating
they could not be penetrating	I could not have penetrated
you could not have penetrated
he could not have penetrated
we could not have penetrated
you could not have penetrated
they could not have penetrated	I could not have been penetrating
you could not have been penetrating
he could not have been penetrating
we could not have been penetrating
you could not have been penetrating
they could not have been penetrating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I penetrate?
could you penetrate?
could he penetrate?
could we penetrate?
could you penetrate?
could they penetrate? 	could I be penetrating?
could you be penetrating?
could he be penetrating?
could we be penetrating?
could you be penetrating?
could they be penetrating? 	could I have penetrated?
could you have penetrated?
could he have penetrated?
could we have penetrated?
could you have penetrated?
could they have penetrated? 	could I have been penetrating?
could you have been penetrating?
could he have been penetrating?
could we have been penetrating?
could you have been penetrating?
could they have been penetrating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not penetrate?
could you not penetrate?
could he not penetrate?
could we not penetrate?
could you not penetrate?
could they not penetrate? 	could I not be penetrating?
could you not be penetrating?
could he not be penetrating?
could we not be penetrating?
could you not be penetrating?
could they not be penetrating? 	could I not have penetrated?
could you not have penetrated?
could he not have penetrated?
could we not have penetrated?
could you not have penetrated?
could they not have penetrated? 	could I not have been penetrating?
could you not have been penetrating?
could he not have been penetrating?
could we not have been penetrating?
could you not have been penetrating?
could they not have been penetrating?