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