could synchronize
Regular verb: synchronize - synchronized- synchronized

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could synchronize
you could synchronize
she could synchronize
we could synchronize
you could synchronize
they could synchronize 	I could be synchronizing
you could be synchronizing
she could be synchronizing
we could be synchronizing
you could be synchronizing
they could be synchronizing	I could have synchronized
you could have synchronized
she could have synchronized
we could have synchronized
you could have synchronized
they could have synchronized	I could have been synchronizing
you could have been synchronizing
she could have been synchronizing
we could have been synchronizing
you could have been synchronizing
they could have been synchronizing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't synchronize
you couldn't synchronize
she couldn't synchronize
we couldn't synchronize
you couldn't synchronize
they couldn't synchronize 	I couldn't be synchronizing
you couldn't be synchronizing
she couldn't be synchronizing
we couldn't be synchronizing
you couldn't be synchronizing
they couldn't be synchronizing	I couldn't have synchronized
you couldn't have synchronized
she couldn't have synchronized
we couldn't have synchronized
you couldn't have synchronized
they couldn't have synchronized	I couldn't have been synchronizing
you couldn't have been synchronizing
she couldn't have been synchronizing
we couldn't have been synchronizing
you couldn't have been synchronizing
they couldn't have been synchronizing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I synchronize?
could you synchronize?
could she synchronize?
could we synchronize?
could you synchronize?
could they synchronize? 	could I be synchronizing?
could you be synchronizing?
could she be synchronizing?
could we be synchronizing?
could you be synchronizing?
could they be synchronizing? 	could I have synchronized?
could you have synchronized?
could she have synchronized?
could we have synchronized?
could you have synchronized?
could they have synchronized? 	could I have been synchronizing?
could you have been synchronizing?
could she have been synchronizing?
could we have been synchronizing?
could you have been synchronizing?
could they have been synchronizing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I synchronize?
couldn't you synchronize?
couldn't she synchronize?
couldn't we synchronize?
couldn't you synchronize?
couldn't they synchronize? 	couldn't I be synchronizing?
couldn't you be synchronizing?
couldn't she be synchronizing?
couldn't we be synchronizing?
couldn't you be synchronizing?
couldn't they be synchronizing? 	couldn't I have synchronized?
couldn't you have synchronized?
couldn't she have synchronized?
couldn't we have synchronized?
couldn't you have synchronized?
couldn't they have synchronized? 	couldn't I have been synchronizing?
couldn't you have been synchronizing?
couldn't she have been synchronizing?
couldn't we have been synchronizing?
couldn't you have been synchronizing?
couldn't they have been synchronizing?