I could check you could check he could check we could check you could check they could check
Forma con V-ing
I could be checking you could be checking he could be checking we could be checking you could be checking they could be checking
Perfetto
I could have checked you could have checked he could have checked we could have checked you could have checked they could have checked
Perfetto con V-ing
I could have been checking you could have been checking he could have been checking we could have been checking you could have been checking they could have been checking
Negazione
Forma semplice
I could not check you could not check he could not check we could not check you could not check they could not check
Forma con V-ing
I could not be checking you could not be checking he could not be checking we could not be checking you could not be checking they could not be checking
Perfetto
I could not have checked you could not have checked he could not have checked we could not have checked you could not have checked they could not have checked
Perfetto con V-ing
I could not have been checking you could not have been checking he could not have been checking we could not have been checking you could not have been checking they could not have been checking
Forma interrogativa
Forma semplice
could I check? could you check? could he check? could we check? could you check? could they check?
Forma con V-ing
could I be checking? could you be checking? could he be checking? could we be checking? could you be checking? could they be checking?
Perfetto
could I have checked? could you have checked? could he have checked? could we have checked? could you have checked? could they have checked?
Perfetto con V-ing
could I have been checking? could you have been checking? could he have been checking? could we have been checking? could you have been checking? could they have been checking?
Forma interro-negativa
Forma semplice
could I not check? could you not check? could he not check? could we not check? could you not check? could they not check?
Forma con V-ing
could I not be checking? could you not be checking? could he not be checking? could we not be checking? could you not be checking? could they not be checking?
Perfetto
could I not have checked? could you not have checked? could he not have checked? could we not have checked? could you not have checked? could they not have checked?
Perfetto con V-ing
could I not have been checking? could you not have been checking? could he not have been checking? could we not have been checking? could you not have been checking? could they not have been checking?