I can undertake you can undertake he can undertake we can undertake you can undertake they can undertake
V-ing form
I can be undertaking you can be undertaking he can be undertaking we can be undertaking you can be undertaking they can be undertaking
Perfect
I can have undertaken you can have undertaken he 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 he can have been undertaking we can have been undertaking you can have been undertaking they can have been undertaking
Negation
Simple form
I can't undertake you can't undertake he can't undertake we can't undertake you can't undertake they can't undertake
V-ing form
I can't be undertaking you can't be undertaking he can't be undertaking we can't be undertaking you can't be undertaking they can't be undertaking
Perfect
I can't have undertaken you can't have undertaken he can't have undertaken we can't have undertaken you can't have undertaken they can't have undertaken
V-ing perfect
I can't have been undertaking you can't have been undertaking he can't have been undertaking we can't have been undertaking you can't have been undertaking they can't have been undertaking
Interrogative form
Simple form
can I undertake? can you undertake? can he undertake? can we undertake? can you undertake? can they undertake?
V-ing form
can I be undertaking? can you be undertaking? can he be undertaking? can we be undertaking? can you be undertaking? can they be undertaking?
Perfect
can I have undertaken? can you have undertaken? can he 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 he have been undertaking? can we have been undertaking? can you have been undertaking? can they have been undertaking?
Interro-negative form
Simple form
can't I undertake? can't you undertake? can't he undertake? can't we undertake? can't you undertake? can't they undertake?
V-ing form
can't I be undertaking? can't you be undertaking? can't he be undertaking? can't we be undertaking? can't you be undertaking? can't they be undertaking?
Perfect
can't I have undertaken? can't you have undertaken? can't he have undertaken? can't we have undertaken? can't you have undertaken? can't they have undertaken?
V-ing perfect
can't I have been undertaking? can't you have been undertaking? can't he have been undertaking? can't we have been undertaking? can't you have been undertaking? can't they have been undertaking?