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