I could zigzag you could zigzag he could zigzag we could zigzag you could zigzag they could zigzag
V-ing form
I could be zigzagging you could be zigzagging he could be zigzagging we could be zigzagging you could be zigzagging they could be zigzagging
Perfect
I could have zigzagged you could have zigzagged he could have zigzagged we could have zigzagged you could have zigzagged they could have zigzagged
V-ing perfect
I could have been zigzagging you could have been zigzagging he could have been zigzagging we could have been zigzagging you could have been zigzagging they could have been zigzagging
Negation
Simple form
I couldn't zigzag you couldn't zigzag he couldn't zigzag we couldn't zigzag you couldn't zigzag they couldn't zigzag
V-ing form
I couldn't be zigzagging you couldn't be zigzagging he couldn't be zigzagging we couldn't be zigzagging you couldn't be zigzagging they couldn't be zigzagging
Perfect
I couldn't have zigzagged you couldn't have zigzagged he couldn't have zigzagged we couldn't have zigzagged you couldn't have zigzagged they couldn't have zigzagged
V-ing perfect
I couldn't have been zigzagging you couldn't have been zigzagging he couldn't have been zigzagging we couldn't have been zigzagging you couldn't have been zigzagging they couldn't have been zigzagging
Interrogative form
Simple form
could I zigzag? could you zigzag? could he zigzag? could we zigzag? could you zigzag? could they zigzag?
V-ing form
could I be zigzagging? could you be zigzagging? could he be zigzagging? could we be zigzagging? could you be zigzagging? could they be zigzagging?
Perfect
could I have zigzagged? could you have zigzagged? could he have zigzagged? could we have zigzagged? could you have zigzagged? could they have zigzagged?
V-ing perfect
could I have been zigzagging? could you have been zigzagging? could he have been zigzagging? could we have been zigzagging? could you have been zigzagging? could they have been zigzagging?
Interro-negative form
Simple form
couldn't I zigzag? couldn't you zigzag? couldn't he zigzag? couldn't we zigzag? couldn't you zigzag? couldn't they zigzag?
V-ing form
couldn't I be zigzagging? couldn't you be zigzagging? couldn't he be zigzagging? couldn't we be zigzagging? couldn't you be zigzagging? couldn't they be zigzagging?
Perfect
couldn't I have zigzagged? couldn't you have zigzagged? couldn't he have zigzagged? couldn't we have zigzagged? couldn't you have zigzagged? couldn't they have zigzagged?
V-ing perfect
couldn't I have been zigzagging? couldn't you have been zigzagging? couldn't he have been zigzagging? couldn't we have been zigzagging? couldn't you have been zigzagging? couldn't they have been zigzagging?