English verb conjugation
CAN BACKFILL

Regular verb: backfill - backfilled - backfilled

Affirmation

Simple form	V-ing form
I can backfill you can backfill he can backfill we can backfill you can backfill they can backfill	I can be backfilling you can be backfilling he can be backfilling we can be backfilling you can be backfilling they can be backfilling
Perfect	V-ing perfect
I can have backfilled you can have backfilled he can have backfilled we can have backfilled you can have backfilled they can have backfilled	I can have been backfilling you can have been backfilling he can have been backfilling we can have been backfilling you can have been backfilling they can have been backfilling

Negation

Simple form	V-ing form
I cannot backfill you cannot backfill he cannot backfill we cannot backfill you cannot backfill they cannot backfill	I cannot be backfilling you cannot be backfilling he cannot be backfilling we cannot be backfilling you cannot be backfilling they cannot be backfilling
Perfect	V-ing perfect
I cannot have backfilled you cannot have backfilled he cannot have backfilled we cannot have backfilled you cannot have backfilled they cannot have backfilled	I cannot have been backfilling you cannot have been backfilling he cannot have been backfilling we cannot have been backfilling you cannot have been backfilling they cannot have been backfilling

Interrogative form

Simple form	V-ing form
can I backfill? can you backfill? can he backfill? can we backfill? can you backfill? can they backfill?	can I be backfilling? can you be backfilling? can he be backfilling? can we be backfilling? can you be backfilling? can they be backfilling?
Perfect	V-ing perfect
can I have backfilled? can you have backfilled? can he have backfilled? can we have backfilled? can you have backfilled? can they have backfilled?	can I have been backfilling? can you have been backfilling? can he have been backfilling? can we have been backfilling? can you have been backfilling? can they have been backfilling?

Interro-negative form

Simple form	V-ing form
can I not backfill? can you not backfill? can he not backfill? can we not backfill? can you not backfill? can they not backfill?	can I not be backfilling? can you not be backfilling? can he not be backfilling? can we not be backfilling? can you not be backfilling? can they not be backfilling?
Perfect	V-ing perfect
can I not have backfilled? can you not have backfilled? can he not have backfilled? can we not have backfilled? can you not have backfilled? can they not have backfilled?	can I not have been backfilling? can you not have been backfilling? can he not have been backfilling? can we not have been backfilling? can you not have been backfilling? can they not have been backfilling?