I can backfire you can backfire he can backfire we can backfire you can backfire they can backfire
V-ing form
I can be backfiring you can be backfiring he can be backfiring we can be backfiring you can be backfiring they can be backfiring
Perfect
I can have backfired you can have backfired he 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 he can have been backfiring we can have been backfiring you can have been backfiring they can have been backfiring
Negation
Simple form
I can't backfire you can't backfire he can't backfire we can't backfire you can't backfire they can't backfire
V-ing form
I can't be backfiring you can't be backfiring he can't be backfiring we can't be backfiring you can't be backfiring they can't be backfiring
Perfect
I can't have backfired you can't have backfired he can't have backfired we can't have backfired you can't have backfired they can't have backfired
V-ing perfect
I can't have been backfiring you can't have been backfiring he can't have been backfiring we can't have been backfiring you can't have been backfiring they can't have been backfiring
Interrogative form
Simple form
can I backfire? can you backfire? can he backfire? can we backfire? can you backfire? can they backfire?
V-ing form
can I be backfiring? can you be backfiring? can he be backfiring? can we be backfiring? can you be backfiring? can they be backfiring?
Perfect
can I have backfired? can you have backfired? can he 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 he have been backfiring? can we have been backfiring? can you have been backfiring? can they have been backfiring?
Interro-negative form
Simple form
can't I backfire? can't you backfire? can't he backfire? can't we backfire? can't you backfire? can't they backfire?
V-ing form
can't I be backfiring? can't you be backfiring? can't he be backfiring? can't we be backfiring? can't you be backfiring? can't they be backfiring?
Perfect
can't I have backfired? can't you have backfired? can't he have backfired? can't we have backfired? can't you have backfired? can't they have backfired?
V-ing perfect
can't I have been backfiring? can't you have been backfiring? can't he have been backfiring? can't we have been backfiring? can't you have been backfiring? can't they have been backfiring?