I could screech you could screech he could screech we could screech you could screech they could screech
V-ing form
I could be screeching you could be screeching he could be screeching we could be screeching you could be screeching they could be screeching
Perfect
I could have screeched you could have screeched he could have screeched we could have screeched you could have screeched they could have screeched
V-ing perfect
I could have been screeching you could have been screeching he could have been screeching we could have been screeching you could have been screeching they could have been screeching
Negation
Simple form
I could not screech you could not screech he could not screech we could not screech you could not screech they could not screech
V-ing form
I could not be screeching you could not be screeching he could not be screeching we could not be screeching you could not be screeching they could not be screeching
Perfect
I could not have screeched you could not have screeched he could not have screeched we could not have screeched you could not have screeched they could not have screeched
V-ing perfect
I could not have been screeching you could not have been screeching he could not have been screeching we could not have been screeching you could not have been screeching they could not have been screeching
Interrogative form
Simple form
could I screech? could you screech? could he screech? could we screech? could you screech? could they screech?
V-ing form
could I be screeching? could you be screeching? could he be screeching? could we be screeching? could you be screeching? could they be screeching?
Perfect
could I have screeched? could you have screeched? could he have screeched? could we have screeched? could you have screeched? could they have screeched?
V-ing perfect
could I have been screeching? could you have been screeching? could he have been screeching? could we have been screeching? could you have been screeching? could they have been screeching?
Interro-negative form
Simple form
could I not screech? could you not screech? could he not screech? could we not screech? could you not screech? could they not screech?
V-ing form
could I not be screeching? could you not be screeching? could he not be screeching? could we not be screeching? could you not be screeching? could they not be screeching?
Perfect
could I not have screeched? could you not have screeched? could he not have screeched? could we not have screeched? could you not have screeched? could they not have screeched?
V-ing perfect
could I not have been screeching? could you not have been screeching? could he not have been screeching? could we not have been screeching? could you not have been screeching? could they not have been screeching?