I can purify you can purify she can purify we can purify you can purify they can purify
V-ing form
I can be purifying you can be purifying she can be purifying we can be purifying you can be purifying they can be purifying
Perfect
I can have purified you can have purified she can have purified we can have purified you can have purified they can have purified
V-ing perfect
I can have been purifying you can have been purifying she can have been purifying we can have been purifying you can have been purifying they can have been purifying
Negation
Simple form
I can't purify you can't purify she can't purify we can't purify you can't purify they can't purify
V-ing form
I can't be purifying you can't be purifying she can't be purifying we can't be purifying you can't be purifying they can't be purifying
Perfect
I can't have purified you can't have purified she can't have purified we can't have purified you can't have purified they can't have purified
V-ing perfect
I can't have been purifying you can't have been purifying she can't have been purifying we can't have been purifying you can't have been purifying they can't have been purifying
Interrogative form
Simple form
can I purify? can you purify? can she purify? can we purify? can you purify? can they purify?
V-ing form
can I be purifying? can you be purifying? can she be purifying? can we be purifying? can you be purifying? can they be purifying?
Perfect
can I have purified? can you have purified? can she have purified? can we have purified? can you have purified? can they have purified?
V-ing perfect
can I have been purifying? can you have been purifying? can she have been purifying? can we have been purifying? can you have been purifying? can they have been purifying?
Interro-negative form
Simple form
can't I purify? can't you purify? can't she purify? can't we purify? can't you purify? can't they purify?
V-ing form
can't I be purifying? can't you be purifying? can't she be purifying? can't we be purifying? can't you be purifying? can't they be purifying?
Perfect
can't I have purified? can't you have purified? can't she have purified? can't we have purified? can't you have purified? can't they have purified?
V-ing perfect
can't I have been purifying? can't you have been purifying? can't she have been purifying? can't we have been purifying? can't you have been purifying? can't they have been purifying?