I could flock you could flock she could flock we could flock you could flock they could flock
V-ing form
I could be flocking you could be flocking she could be flocking we could be flocking you could be flocking they could be flocking
Perfect
I could have flocked you could have flocked she could have flocked we could have flocked you could have flocked they could have flocked
V-ing perfect
I could have been flocking you could have been flocking she could have been flocking we could have been flocking you could have been flocking they could have been flocking
Negation
Simple form
I couldn't flock you couldn't flock she couldn't flock we couldn't flock you couldn't flock they couldn't flock
V-ing form
I couldn't be flocking you couldn't be flocking she couldn't be flocking we couldn't be flocking you couldn't be flocking they couldn't be flocking
Perfect
I couldn't have flocked you couldn't have flocked she couldn't have flocked we couldn't have flocked you couldn't have flocked they couldn't have flocked
V-ing perfect
I couldn't have been flocking you couldn't have been flocking she couldn't have been flocking we couldn't have been flocking you couldn't have been flocking they couldn't have been flocking
Interrogative form
Simple form
could I flock? could you flock? could she flock? could we flock? could you flock? could they flock?
V-ing form
could I be flocking? could you be flocking? could she be flocking? could we be flocking? could you be flocking? could they be flocking?
Perfect
could I have flocked? could you have flocked? could she have flocked? could we have flocked? could you have flocked? could they have flocked?
V-ing perfect
could I have been flocking? could you have been flocking? could she have been flocking? could we have been flocking? could you have been flocking? could they have been flocking?
Interro-negative form
Simple form
couldn't I flock? couldn't you flock? couldn't she flock? couldn't we flock? couldn't you flock? couldn't they flock?
V-ing form
couldn't I be flocking? couldn't you be flocking? couldn't she be flocking? couldn't we be flocking? couldn't you be flocking? couldn't they be flocking?
Perfect
couldn't I have flocked? couldn't you have flocked? couldn't she have flocked? couldn't we have flocked? couldn't you have flocked? couldn't they have flocked?
V-ing perfect
couldn't I have been flocking? couldn't you have been flocking? couldn't she have been flocking? couldn't we have been flocking? couldn't you have been flocking? couldn't they have been flocking?