I can filter you can filter she can filter we can filter you can filter they can filter
V-ing form
I can be filtering you can be filtering she can be filtering we can be filtering you can be filtering they can be filtering
Perfect
I can have filtered you can have filtered she can have filtered we can have filtered you can have filtered they can have filtered
V-ing perfect
I can have been filtering you can have been filtering she can have been filtering we can have been filtering you can have been filtering they can have been filtering
Negation
Simple form
I can't filter you can't filter she can't filter we can't filter you can't filter they can't filter
V-ing form
I can't be filtering you can't be filtering she can't be filtering we can't be filtering you can't be filtering they can't be filtering
Perfect
I can't have filtered you can't have filtered she can't have filtered we can't have filtered you can't have filtered they can't have filtered
V-ing perfect
I can't have been filtering you can't have been filtering she can't have been filtering we can't have been filtering you can't have been filtering they can't have been filtering
Interrogative form
Simple form
can I filter? can you filter? can she filter? can we filter? can you filter? can they filter?
V-ing form
can I be filtering? can you be filtering? can she be filtering? can we be filtering? can you be filtering? can they be filtering?
Perfect
can I have filtered? can you have filtered? can she have filtered? can we have filtered? can you have filtered? can they have filtered?
V-ing perfect
can I have been filtering? can you have been filtering? can she have been filtering? can we have been filtering? can you have been filtering? can they have been filtering?
Interro-negative form
Simple form
can't I filter? can't you filter? can't she filter? can't we filter? can't you filter? can't they filter?
V-ing form
can't I be filtering? can't you be filtering? can't she be filtering? can't we be filtering? can't you be filtering? can't they be filtering?
Perfect
can't I have filtered? can't you have filtered? can't she have filtered? can't we have filtered? can't you have filtered? can't they have filtered?
V-ing perfect
can't I have been filtering? can't you have been filtering? can't she have been filtering? can't we have been filtering? can't you have been filtering? can't they have been filtering?