I could backspace you could backspace she could backspace we could backspace you could backspace they could backspace
V-ing form
I could be backspacing you could be backspacing she could be backspacing we could be backspacing you could be backspacing they could be backspacing
Perfect
I could have backspaced you could have backspaced she could have backspaced we could have backspaced you could have backspaced they could have backspaced
V-ing perfect
I could have been backspacing you could have been backspacing she could have been backspacing we could have been backspacing you could have been backspacing they could have been backspacing
Negation
Simple form
I could not backspace you could not backspace she could not backspace we could not backspace you could not backspace they could not backspace
V-ing form
I could not be backspacing you could not be backspacing she could not be backspacing we could not be backspacing you could not be backspacing they could not be backspacing
Perfect
I could not have backspaced you could not have backspaced she could not have backspaced we could not have backspaced you could not have backspaced they could not have backspaced
V-ing perfect
I could not have been backspacing you could not have been backspacing she could not have been backspacing we could not have been backspacing you could not have been backspacing they could not have been backspacing
Interrogative form
Simple form
could I backspace? could you backspace? could she backspace? could we backspace? could you backspace? could they backspace?
V-ing form
could I be backspacing? could you be backspacing? could she be backspacing? could we be backspacing? could you be backspacing? could they be backspacing?
Perfect
could I have backspaced? could you have backspaced? could she have backspaced? could we have backspaced? could you have backspaced? could they have backspaced?
V-ing perfect
could I have been backspacing? could you have been backspacing? could she have been backspacing? could we have been backspacing? could you have been backspacing? could they have been backspacing?
Interro-negative form
Simple form
could I not backspace? could you not backspace? could she not backspace? could we not backspace? could you not backspace? could they not backspace?
V-ing form
could I not be backspacing? could you not be backspacing? could she not be backspacing? could we not be backspacing? could you not be backspacing? could they not be backspacing?
Perfect
could I not have backspaced? could you not have backspaced? could she not have backspaced? could we not have backspaced? could you not have backspaced? could they not have backspaced?
V-ing perfect
could I not have been backspacing? could you not have been backspacing? could she not have been backspacing? could we not have been backspacing? could you not have been backspacing? could they not have been backspacing?