I could classify you could classify he could classify we could classify you could classify they could classify
V-ing form
I could be classifying you could be classifying he could be classifying we could be classifying you could be classifying they could be classifying
Perfect
I could have classified you could have classified he could have classified we could have classified you could have classified they could have classified
V-ing perfect
I could have been classifying you could have been classifying he could have been classifying we could have been classifying you could have been classifying they could have been classifying
Negation
Simple form
I could not classify you could not classify he could not classify we could not classify you could not classify they could not classify
V-ing form
I could not be classifying you could not be classifying he could not be classifying we could not be classifying you could not be classifying they could not be classifying
Perfect
I could not have classified you could not have classified he could not have classified we could not have classified you could not have classified they could not have classified
V-ing perfect
I could not have been classifying you could not have been classifying he could not have been classifying we could not have been classifying you could not have been classifying they could not have been classifying
Interrogative form
Simple form
could I classify? could you classify? could he classify? could we classify? could you classify? could they classify?
V-ing form
could I be classifying? could you be classifying? could he be classifying? could we be classifying? could you be classifying? could they be classifying?
Perfect
could I have classified? could you have classified? could he have classified? could we have classified? could you have classified? could they have classified?
V-ing perfect
could I have been classifying? could you have been classifying? could he have been classifying? could we have been classifying? could you have been classifying? could they have been classifying?
Interro-negative form
Simple form
could I not classify? could you not classify? could he not classify? could we not classify? could you not classify? could they not classify?
V-ing form
could I not be classifying? could you not be classifying? could he not be classifying? could we not be classifying? could you not be classifying? could they not be classifying?
Perfect
could I not have classified? could you not have classified? could he not have classified? could we not have classified? could you not have classified? could they not have classified?
V-ing perfect
could I not have been classifying? could you not have been classifying? could he not have been classifying? could we not have been classifying? could you not have been classifying? could they not have been classifying?