could interrogate
Regular verb: interrogate - interrogated- interrogated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could interrogate
you could interrogate
she could interrogate
we could interrogate
you could interrogate
they could interrogate 	I could be interrogating
you could be interrogating
she could be interrogating
we could be interrogating
you could be interrogating
they could be interrogating	I could have interrogated
you could have interrogated
she could have interrogated
we could have interrogated
you could have interrogated
they could have interrogated	I could have been interrogating
you could have been interrogating
she could have been interrogating
we could have been interrogating
you could have been interrogating
they could have been interrogating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't interrogate
you couldn't interrogate
she couldn't interrogate
we couldn't interrogate
you couldn't interrogate
they couldn't interrogate 	I couldn't be interrogating
you couldn't be interrogating
she couldn't be interrogating
we couldn't be interrogating
you couldn't be interrogating
they couldn't be interrogating	I couldn't have interrogated
you couldn't have interrogated
she couldn't have interrogated
we couldn't have interrogated
you couldn't have interrogated
they couldn't have interrogated	I couldn't have been interrogating
you couldn't have been interrogating
she couldn't have been interrogating
we couldn't have been interrogating
you couldn't have been interrogating
they couldn't have been interrogating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I interrogate?
could you interrogate?
could she interrogate?
could we interrogate?
could you interrogate?
could they interrogate? 	could I be interrogating?
could you be interrogating?
could she be interrogating?
could we be interrogating?
could you be interrogating?
could they be interrogating? 	could I have interrogated?
could you have interrogated?
could she have interrogated?
could we have interrogated?
could you have interrogated?
could they have interrogated? 	could I have been interrogating?
could you have been interrogating?
could she have been interrogating?
could we have been interrogating?
could you have been interrogating?
could they have been interrogating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I interrogate?
couldn't you interrogate?
couldn't she interrogate?
couldn't we interrogate?
couldn't you interrogate?
couldn't they interrogate? 	couldn't I be interrogating?
couldn't you be interrogating?
couldn't she be interrogating?
couldn't we be interrogating?
couldn't you be interrogating?
couldn't they be interrogating? 	couldn't I have interrogated?
couldn't you have interrogated?
couldn't she have interrogated?
couldn't we have interrogated?
couldn't you have interrogated?
couldn't they have interrogated? 	couldn't I have been interrogating?
couldn't you have been interrogating?
couldn't she have been interrogating?
couldn't we have been interrogating?
couldn't you have been interrogating?
couldn't they have been interrogating?