could alphabetize
Regular verb: alphabetize - alphabetized- alphabetized

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could alphabetize
you could alphabetize
he could alphabetize
we could alphabetize
you could alphabetize
they could alphabetize 	I could be alphabetizing
you could be alphabetizing
he could be alphabetizing
we could be alphabetizing
you could be alphabetizing
they could be alphabetizing	I could have alphabetized
you could have alphabetized
he could have alphabetized
we could have alphabetized
you could have alphabetized
they could have alphabetized	I could have been alphabetizing
you could have been alphabetizing
he could have been alphabetizing
we could have been alphabetizing
you could have been alphabetizing
they could have been alphabetizing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't alphabetize
you couldn't alphabetize
he couldn't alphabetize
we couldn't alphabetize
you couldn't alphabetize
they couldn't alphabetize 	I couldn't be alphabetizing
you couldn't be alphabetizing
he couldn't be alphabetizing
we couldn't be alphabetizing
you couldn't be alphabetizing
they couldn't be alphabetizing	I couldn't have alphabetized
you couldn't have alphabetized
he couldn't have alphabetized
we couldn't have alphabetized
you couldn't have alphabetized
they couldn't have alphabetized	I couldn't have been alphabetizing
you couldn't have been alphabetizing
he couldn't have been alphabetizing
we couldn't have been alphabetizing
you couldn't have been alphabetizing
they couldn't have been alphabetizing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I alphabetize?
could you alphabetize?
could he alphabetize?
could we alphabetize?
could you alphabetize?
could they alphabetize? 	could I be alphabetizing?
could you be alphabetizing?
could he be alphabetizing?
could we be alphabetizing?
could you be alphabetizing?
could they be alphabetizing? 	could I have alphabetized?
could you have alphabetized?
could he have alphabetized?
could we have alphabetized?
could you have alphabetized?
could they have alphabetized? 	could I have been alphabetizing?
could you have been alphabetizing?
could he have been alphabetizing?
could we have been alphabetizing?
could you have been alphabetizing?
could they have been alphabetizing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I alphabetize?
couldn't you alphabetize?
couldn't he alphabetize?
couldn't we alphabetize?
couldn't you alphabetize?
couldn't they alphabetize? 	couldn't I be alphabetizing?
couldn't you be alphabetizing?
couldn't he be alphabetizing?
couldn't we be alphabetizing?
couldn't you be alphabetizing?
couldn't they be alphabetizing? 	couldn't I have alphabetized?
couldn't you have alphabetized?
couldn't he have alphabetized?
couldn't we have alphabetized?
couldn't you have alphabetized?
couldn't they have alphabetized? 	couldn't I have been alphabetizing?
couldn't you have been alphabetizing?
couldn't he have been alphabetizing?
couldn't we have been alphabetizing?
couldn't you have been alphabetizing?
couldn't they have been alphabetizing?