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