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