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