I can descend you can descend she can descend we can descend you can descend they can descend
V-ing form
I can be descending you can be descending she can be descending we can be descending you can be descending they can be descending
Perfect
I can have descended you can have descended she can have descended we can have descended you can have descended they can have descended
V-ing perfect
I can have been descending you can have been descending she can have been descending we can have been descending you can have been descending they can have been descending
Negation
Simple form
I cannot descend you cannot descend she cannot descend we cannot descend you cannot descend they cannot descend
V-ing form
I cannot be descending you cannot be descending she cannot be descending we cannot be descending you cannot be descending they cannot be descending
Perfect
I cannot have descended you cannot have descended she cannot have descended we cannot have descended you cannot have descended they cannot have descended
V-ing perfect
I cannot have been descending you cannot have been descending she cannot have been descending we cannot have been descending you cannot have been descending they cannot have been descending
Interrogative form
Simple form
can I descend? can you descend? can she descend? can we descend? can you descend? can they descend?
V-ing form
can I be descending? can you be descending? can she be descending? can we be descending? can you be descending? can they be descending?
Perfect
can I have descended? can you have descended? can she have descended? can we have descended? can you have descended? can they have descended?
V-ing perfect
can I have been descending? can you have been descending? can she have been descending? can we have been descending? can you have been descending? can they have been descending?
Interro-negative form
Simple form
can I not descend? can you not descend? can she not descend? can we not descend? can you not descend? can they not descend?
V-ing form
can I not be descending? can you not be descending? can she not be descending? can we not be descending? can you not be descending? can they not be descending?
Perfect
can I not have descended? can you not have descended? can she not have descended? can we not have descended? can you not have descended? can they not have descended?
V-ing perfect
can I not have been descending? can you not have been descending? can she not have been descending? can we not have been descending? can you not have been descending? can they not have been descending?