I could fractionate you could fractionate he could fractionate we could fractionate you could fractionate they could fractionate
V-ing form
I could be fractionating you could be fractionating he could be fractionating we could be fractionating you could be fractionating they could be fractionating
Perfect
I could have fractionated you could have fractionated he could have fractionated we could have fractionated you could have fractionated they could have fractionated
V-ing perfect
I could have been fractionating you could have been fractionating he could have been fractionating we could have been fractionating you could have been fractionating they could have been fractionating
Negation
Simple form
I could not fractionate you could not fractionate he could not fractionate we could not fractionate you could not fractionate they could not fractionate
V-ing form
I could not be fractionating you could not be fractionating he could not be fractionating we could not be fractionating you could not be fractionating they could not be fractionating
Perfect
I could not have fractionated you could not have fractionated he could not have fractionated we could not have fractionated you could not have fractionated they could not have fractionated
V-ing perfect
I could not have been fractionating you could not have been fractionating he could not have been fractionating we could not have been fractionating you could not have been fractionating they could not have been fractionating
Interrogative form
Simple form
could I fractionate? could you fractionate? could he fractionate? could we fractionate? could you fractionate? could they fractionate?
V-ing form
could I be fractionating? could you be fractionating? could he be fractionating? could we be fractionating? could you be fractionating? could they be fractionating?
Perfect
could I have fractionated? could you have fractionated? could he have fractionated? could we have fractionated? could you have fractionated? could they have fractionated?
V-ing perfect
could I have been fractionating? could you have been fractionating? could he have been fractionating? could we have been fractionating? could you have been fractionating? could they have been fractionating?
Interro-negative form
Simple form
could I not fractionate? could you not fractionate? could he not fractionate? could we not fractionate? could you not fractionate? could they not fractionate?
V-ing form
could I not be fractionating? could you not be fractionating? could he not be fractionating? could we not be fractionating? could you not be fractionating? could they not be fractionating?
Perfect
could I not have fractionated? could you not have fractionated? could he not have fractionated? could we not have fractionated? could you not have fractionated? could they not have fractionated?
V-ing perfect
could I not have been fractionating? could you not have been fractionating? could he not have been fractionating? could we not have been fractionating? could you not have been fractionating? could they not have been fractionating?