I could unlatch you could unlatch she could unlatch we could unlatch you could unlatch they could unlatch
V-ing form
I could be unlatching you could be unlatching she could be unlatching we could be unlatching you could be unlatching they could be unlatching
Perfect
I could have unlatched you could have unlatched she could have unlatched we could have unlatched you could have unlatched they could have unlatched
V-ing perfect
I could have been unlatching you could have been unlatching she could have been unlatching we could have been unlatching you could have been unlatching they could have been unlatching
Negation
Simple form
I could not unlatch you could not unlatch she could not unlatch we could not unlatch you could not unlatch they could not unlatch
V-ing form
I could not be unlatching you could not be unlatching she could not be unlatching we could not be unlatching you could not be unlatching they could not be unlatching
Perfect
I could not have unlatched you could not have unlatched she could not have unlatched we could not have unlatched you could not have unlatched they could not have unlatched
V-ing perfect
I could not have been unlatching you could not have been unlatching she could not have been unlatching we could not have been unlatching you could not have been unlatching they could not have been unlatching
Interrogative form
Simple form
could I unlatch? could you unlatch? could she unlatch? could we unlatch? could you unlatch? could they unlatch?
V-ing form
could I be unlatching? could you be unlatching? could she be unlatching? could we be unlatching? could you be unlatching? could they be unlatching?
Perfect
could I have unlatched? could you have unlatched? could she have unlatched? could we have unlatched? could you have unlatched? could they have unlatched?
V-ing perfect
could I have been unlatching? could you have been unlatching? could she have been unlatching? could we have been unlatching? could you have been unlatching? could they have been unlatching?
Interro-negative form
Simple form
could I not unlatch? could you not unlatch? could she not unlatch? could we not unlatch? could you not unlatch? could they not unlatch?
V-ing form
could I not be unlatching? could you not be unlatching? could she not be unlatching? could we not be unlatching? could you not be unlatching? could they not be unlatching?
Perfect
could I not have unlatched? could you not have unlatched? could she not have unlatched? could we not have unlatched? could you not have unlatched? could they not have unlatched?
V-ing perfect
could I not have been unlatching? could you not have been unlatching? could she not have been unlatching? could we not have been unlatching? could you not have been unlatching? could they not have been unlatching?