could comprehend
Regular verb: comprehend - comprehended- comprehended

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could comprehend
you could comprehend
she could comprehend
we could comprehend
you could comprehend
they could comprehend 	I could be comprehending
you could be comprehending
she could be comprehending
we could be comprehending
you could be comprehending
they could be comprehending	I could have comprehended
you could have comprehended
she could have comprehended
we could have comprehended
you could have comprehended
they could have comprehended	I could have been comprehending
you could have been comprehending
she could have been comprehending
we could have been comprehending
you could have been comprehending
they could have been comprehending	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not comprehend
you could not comprehend
she could not comprehend
we could not comprehend
you could not comprehend
they could not comprehend 	I could not be comprehending
you could not be comprehending
she could not be comprehending
we could not be comprehending
you could not be comprehending
they could not be comprehending	I could not have comprehended
you could not have comprehended
she could not have comprehended
we could not have comprehended
you could not have comprehended
they could not have comprehended	I could not have been comprehending
you could not have been comprehending
she could not have been comprehending
we could not have been comprehending
you could not have been comprehending
they could not have been comprehending	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I comprehend?
could you comprehend?
could she comprehend?
could we comprehend?
could you comprehend?
could they comprehend? 	could I be comprehending?
could you be comprehending?
could she be comprehending?
could we be comprehending?
could you be comprehending?
could they be comprehending? 	could I have comprehended?
could you have comprehended?
could she have comprehended?
could we have comprehended?
could you have comprehended?
could they have comprehended? 	could I have been comprehending?
could you have been comprehending?
could she have been comprehending?
could we have been comprehending?
could you have been comprehending?
could they have been comprehending? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not comprehend?
could you not comprehend?
could she not comprehend?
could we not comprehend?
could you not comprehend?
could they not comprehend? 	could I not be comprehending?
could you not be comprehending?
could she not be comprehending?
could we not be comprehending?
could you not be comprehending?
could they not be comprehending? 	could I not have comprehended?
could you not have comprehended?
could she not have comprehended?
could we not have comprehended?
could you not have comprehended?
could they not have comprehended? 	could I not have been comprehending?
could you not have been comprehending?
could she not have been comprehending?
could we not have been comprehending?
could you not have been comprehending?
could they not have been comprehending?