I can backfire you can backfire she can backfire we can backfire you can backfire they can backfire
V-ing form
I can be backfiring you can be backfiring she can be backfiring we can be backfiring you can be backfiring they can be backfiring
Perfect
I can have backfired you can have backfired she can have backfired we can have backfired you can have backfired they can have backfired
V-ing perfect
I can have been backfiring you can have been backfiring she can have been backfiring we can have been backfiring you can have been backfiring they can have been backfiring
Negation
Simple form
I cannot backfire you cannot backfire she cannot backfire we cannot backfire you cannot backfire they cannot backfire
V-ing form
I cannot be backfiring you cannot be backfiring she cannot be backfiring we cannot be backfiring you cannot be backfiring they cannot be backfiring
Perfect
I cannot have backfired you cannot have backfired she cannot have backfired we cannot have backfired you cannot have backfired they cannot have backfired
V-ing perfect
I cannot have been backfiring you cannot have been backfiring she cannot have been backfiring we cannot have been backfiring you cannot have been backfiring they cannot have been backfiring
Interrogative form
Simple form
can I backfire? can you backfire? can she backfire? can we backfire? can you backfire? can they backfire?
V-ing form
can I be backfiring? can you be backfiring? can she be backfiring? can we be backfiring? can you be backfiring? can they be backfiring?
Perfect
can I have backfired? can you have backfired? can she have backfired? can we have backfired? can you have backfired? can they have backfired?
V-ing perfect
can I have been backfiring? can you have been backfiring? can she have been backfiring? can we have been backfiring? can you have been backfiring? can they have been backfiring?
Interro-negative form
Simple form
can I not backfire? can you not backfire? can she not backfire? can we not backfire? can you not backfire? can they not backfire?
V-ing form
can I not be backfiring? can you not be backfiring? can she not be backfiring? can we not be backfiring? can you not be backfiring? can they not be backfiring?
Perfect
can I not have backfired? can you not have backfired? can she not have backfired? can we not have backfired? can you not have backfired? can they not have backfired?
V-ing perfect
can I not have been backfiring? can you not have been backfiring? can she not have been backfiring? can we not have been backfiring? can you not have been backfiring? can they not have been backfiring?