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