I could purify you could purify he could purify we could purify you could purify they could purify
Forme en V-ing
I could be purifying you could be purifying he could be purifying we could be purifying you could be purifying they could be purifying
Perfect
I could have purified you could have purified he could have purified we could have purified you could have purified they could have purified
Perfect en V-ing
I could have been purifying you could have been purifying he could have been purifying we could have been purifying you could have been purifying they could have been purifying
Négation
Forme simple
I could not purify you could not purify he could not purify we could not purify you could not purify they could not purify
Forme en V-ing
I could not be purifying you could not be purifying he could not be purifying we could not be purifying you could not be purifying they could not be purifying
Perfect
I could not have purified you could not have purified he could not have purified we could not have purified you could not have purified they could not have purified
Perfect en V-ing
I could not have been purifying you could not have been purifying he could not have been purifying we could not have been purifying you could not have been purifying they could not have been purifying
Forme interrogative
Forme simple
could I purify? could you purify? could he purify? could we purify? could you purify? could they purify?
Forme en V-ing
could I be purifying? could you be purifying? could he be purifying? could we be purifying? could you be purifying? could they be purifying?
Perfect
could I have purified? could you have purified? could he have purified? could we have purified? could you have purified? could they have purified?
Perfect en V-ing
could I have been purifying? could you have been purifying? could he have been purifying? could we have been purifying? could you have been purifying? could they have been purifying?
Forme interro-négative
Forme simple
could I not purify? could you not purify? could he not purify? could we not purify? could you not purify? could they not purify?
Forme en V-ing
could I not be purifying? could you not be purifying? could he not be purifying? could we not be purifying? could you not be purifying? could they not be purifying?
Perfect
could I not have purified? could you not have purified? could he not have purified? could we not have purified? could you not have purified? could they not have purified?
Perfect en V-ing
could I not have been purifying? could you not have been purifying? could he not have been purifying? could we not have been purifying? could you not have been purifying? could they not have been purifying?