I can purify you can purify he can purify we can purify you can purify they can purify
V-ing form
I can be purifying you can be purifying he can be purifying we can be purifying you can be purifying they can be purifying
Perfect
I can have purified you can have purified he 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 he 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 he 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 he 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 he 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 he 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 he purify? can we purify? can you purify? can they purify?
V-ing form
can I be purifying? can you be purifying? can he be purifying? can we be purifying? can you be purifying? can they be purifying?
Perfect
can I have purified? can you have purified? can he 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 he 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 he 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 he 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 he 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 he have been purifying? can't we have been purifying? can't you have been purifying? can't they have been purifying?