could singularize
Regular verb: singularize - singularized- singularized

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could singularize
you could singularize
he could singularize
we could singularize
you could singularize
they could singularize 	I could be singularizing
you could be singularizing
he could be singularizing
we could be singularizing
you could be singularizing
they could be singularizing	I could have singularized
you could have singularized
he could have singularized
we could have singularized
you could have singularized
they could have singularized	I could have been singularizing
you could have been singularizing
he could have been singularizing
we could have been singularizing
you could have been singularizing
they could have been singularizing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't singularize
you couldn't singularize
he couldn't singularize
we couldn't singularize
you couldn't singularize
they couldn't singularize 	I couldn't be singularizing
you couldn't be singularizing
he couldn't be singularizing
we couldn't be singularizing
you couldn't be singularizing
they couldn't be singularizing	I couldn't have singularized
you couldn't have singularized
he couldn't have singularized
we couldn't have singularized
you couldn't have singularized
they couldn't have singularized	I couldn't have been singularizing
you couldn't have been singularizing
he couldn't have been singularizing
we couldn't have been singularizing
you couldn't have been singularizing
they couldn't have been singularizing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I singularize?
could you singularize?
could he singularize?
could we singularize?
could you singularize?
could they singularize? 	could I be singularizing?
could you be singularizing?
could he be singularizing?
could we be singularizing?
could you be singularizing?
could they be singularizing? 	could I have singularized?
could you have singularized?
could he have singularized?
could we have singularized?
could you have singularized?
could they have singularized? 	could I have been singularizing?
could you have been singularizing?
could he have been singularizing?
could we have been singularizing?
could you have been singularizing?
could they have been singularizing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I singularize?
couldn't you singularize?
couldn't he singularize?
couldn't we singularize?
couldn't you singularize?
couldn't they singularize? 	couldn't I be singularizing?
couldn't you be singularizing?
couldn't he be singularizing?
couldn't we be singularizing?
couldn't you be singularizing?
couldn't they be singularizing? 	couldn't I have singularized?
couldn't you have singularized?
couldn't he have singularized?
couldn't we have singularized?
couldn't you have singularized?
couldn't they have singularized? 	couldn't I have been singularizing?
couldn't you have been singularizing?
couldn't he have been singularizing?
couldn't we have been singularizing?
couldn't you have been singularizing?
couldn't they have been singularizing?