could approximate
Regular verb: approximate - approximated- approximated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could approximate
you could approximate
she could approximate
we could approximate
you could approximate
they could approximate 	I could be approximating
you could be approximating
she could be approximating
we could be approximating
you could be approximating
they could be approximating	I could have approximated
you could have approximated
she could have approximated
we could have approximated
you could have approximated
they could have approximated	I could have been approximating
you could have been approximating
she could have been approximating
we could have been approximating
you could have been approximating
they could have been approximating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't approximate
you couldn't approximate
she couldn't approximate
we couldn't approximate
you couldn't approximate
they couldn't approximate 	I couldn't be approximating
you couldn't be approximating
she couldn't be approximating
we couldn't be approximating
you couldn't be approximating
they couldn't be approximating	I couldn't have approximated
you couldn't have approximated
she couldn't have approximated
we couldn't have approximated
you couldn't have approximated
they couldn't have approximated	I couldn't have been approximating
you couldn't have been approximating
she couldn't have been approximating
we couldn't have been approximating
you couldn't have been approximating
they couldn't have been approximating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I approximate?
could you approximate?
could she approximate?
could we approximate?
could you approximate?
could they approximate? 	could I be approximating?
could you be approximating?
could she be approximating?
could we be approximating?
could you be approximating?
could they be approximating? 	could I have approximated?
could you have approximated?
could she have approximated?
could we have approximated?
could you have approximated?
could they have approximated? 	could I have been approximating?
could you have been approximating?
could she have been approximating?
could we have been approximating?
could you have been approximating?
could they have been approximating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I approximate?
couldn't you approximate?
couldn't she approximate?
couldn't we approximate?
couldn't you approximate?
couldn't they approximate? 	couldn't I be approximating?
couldn't you be approximating?
couldn't she be approximating?
couldn't we be approximating?
couldn't you be approximating?
couldn't they be approximating? 	couldn't I have approximated?
couldn't you have approximated?
couldn't she have approximated?
couldn't we have approximated?
couldn't you have approximated?
couldn't they have approximated? 	couldn't I have been approximating?
couldn't you have been approximating?
couldn't she have been approximating?
couldn't we have been approximating?
couldn't you have been approximating?
couldn't they have been approximating?