I could appreciate you could appreciate he could appreciate we could appreciate you could appreciate they could appreciate
V-ing form
I could be appreciating you could be appreciating he could be appreciating we could be appreciating you could be appreciating they could be appreciating
Perfect
I could have appreciated you could have appreciated he could have appreciated we could have appreciated you could have appreciated they could have appreciated
V-ing perfect
I could have been appreciating you could have been appreciating he could have been appreciating we could have been appreciating you could have been appreciating they could have been appreciating
Negation
Simple form
I could not appreciate you could not appreciate he could not appreciate we could not appreciate you could not appreciate they could not appreciate
V-ing form
I could not be appreciating you could not be appreciating he could not be appreciating we could not be appreciating you could not be appreciating they could not be appreciating
Perfect
I could not have appreciated you could not have appreciated he could not have appreciated we could not have appreciated you could not have appreciated they could not have appreciated
V-ing perfect
I could not have been appreciating you could not have been appreciating he could not have been appreciating we could not have been appreciating you could not have been appreciating they could not have been appreciating
Interrogative form
Simple form
could I appreciate? could you appreciate? could he appreciate? could we appreciate? could you appreciate? could they appreciate?
V-ing form
could I be appreciating? could you be appreciating? could he be appreciating? could we be appreciating? could you be appreciating? could they be appreciating?
Perfect
could I have appreciated? could you have appreciated? could he have appreciated? could we have appreciated? could you have appreciated? could they have appreciated?
V-ing perfect
could I have been appreciating? could you have been appreciating? could he have been appreciating? could we have been appreciating? could you have been appreciating? could they have been appreciating?
Interro-negative form
Simple form
could I not appreciate? could you not appreciate? could he not appreciate? could we not appreciate? could you not appreciate? could they not appreciate?
V-ing form
could I not be appreciating? could you not be appreciating? could he not be appreciating? could we not be appreciating? could you not be appreciating? could they not be appreciating?
Perfect
could I not have appreciated? could you not have appreciated? could he not have appreciated? could we not have appreciated? could you not have appreciated? could they not have appreciated?
V-ing perfect
could I not have been appreciating? could you not have been appreciating? could he not have been appreciating? could we not have been appreciating? could you not have been appreciating? could they not have been appreciating?