I could undertake you could undertake she could undertake we could undertake you could undertake they could undertake
V-ing form
I could be undertaking you could be undertaking she could be undertaking we could be undertaking you could be undertaking they could be undertaking
Perfect
I could have undertaken you could have undertaken she could have undertaken we could have undertaken you could have undertaken they could have undertaken
V-ing perfect
I could have been undertaking you could have been undertaking she could have been undertaking we could have been undertaking you could have been undertaking they could have been undertaking
Negation
Simple form
I could not undertake you could not undertake she could not undertake we could not undertake you could not undertake they could not undertake
V-ing form
I could not be undertaking you could not be undertaking she could not be undertaking we could not be undertaking you could not be undertaking they could not be undertaking
Perfect
I could not have undertaken you could not have undertaken she could not have undertaken we could not have undertaken you could not have undertaken they could not have undertaken
V-ing perfect
I could not have been undertaking you could not have been undertaking she could not have been undertaking we could not have been undertaking you could not have been undertaking they could not have been undertaking
Interrogative form
Simple form
could I undertake? could you undertake? could she undertake? could we undertake? could you undertake? could they undertake?
V-ing form
could I be undertaking? could you be undertaking? could she be undertaking? could we be undertaking? could you be undertaking? could they be undertaking?
Perfect
could I have undertaken? could you have undertaken? could she have undertaken? could we have undertaken? could you have undertaken? could they have undertaken?
V-ing perfect
could I have been undertaking? could you have been undertaking? could she have been undertaking? could we have been undertaking? could you have been undertaking? could they have been undertaking?
Interro-negative form
Simple form
could I not undertake? could you not undertake? could she not undertake? could we not undertake? could you not undertake? could they not undertake?
V-ing form
could I not be undertaking? could you not be undertaking? could she not be undertaking? could we not be undertaking? could you not be undertaking? could they not be undertaking?
Perfect
could I not have undertaken? could you not have undertaken? could she not have undertaken? could we not have undertaken? could you not have undertaken? could they not have undertaken?
V-ing perfect
could I not have been undertaking? could you not have been undertaking? could she not have been undertaking? could we not have been undertaking? could you not have been undertaking? could they not have been undertaking?