I could undertain you could undertain she could undertain we could undertain you could undertain they could undertain
V-ing form
I could be undertaining you could be undertaining she could be undertaining we could be undertaining you could be undertaining they could be undertaining
Perfect
I could have undertained you could have undertained she could have undertained we could have undertained you could have undertained they could have undertained
V-ing perfect
I could have been undertaining you could have been undertaining she could have been undertaining we could have been undertaining you could have been undertaining they could have been undertaining
Negation
Simple form
I could not undertain you could not undertain she could not undertain we could not undertain you could not undertain they could not undertain
V-ing form
I could not be undertaining you could not be undertaining she could not be undertaining we could not be undertaining you could not be undertaining they could not be undertaining
Perfect
I could not have undertained you could not have undertained she could not have undertained we could not have undertained you could not have undertained they could not have undertained
V-ing perfect
I could not have been undertaining you could not have been undertaining she could not have been undertaining we could not have been undertaining you could not have been undertaining they could not have been undertaining
Interrogative form
Simple form
could I undertain? could you undertain? could she undertain? could we undertain? could you undertain? could they undertain?
V-ing form
could I be undertaining? could you be undertaining? could she be undertaining? could we be undertaining? could you be undertaining? could they be undertaining?
Perfect
could I have undertained? could you have undertained? could she have undertained? could we have undertained? could you have undertained? could they have undertained?
V-ing perfect
could I have been undertaining? could you have been undertaining? could she have been undertaining? could we have been undertaining? could you have been undertaining? could they have been undertaining?
Interro-negative form
Simple form
could I not undertain? could you not undertain? could she not undertain? could we not undertain? could you not undertain? could they not undertain?
V-ing form
could I not be undertaining? could you not be undertaining? could she not be undertaining? could we not be undertaining? could you not be undertaining? could they not be undertaining?
Perfect
could I not have undertained? could you not have undertained? could she not have undertained? could we not have undertained? could you not have undertained? could they not have undertained?
V-ing perfect
could I not have been undertaining? could you not have been undertaining? could she not have been undertaining? could we not have been undertaining? could you not have been undertaining? could they not have been undertaining?