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