I could discard you could discard she could discard we could discard you could discard they could discard
V-ing form
I could be discarding you could be discarding she could be discarding we could be discarding you could be discarding they could be discarding
Perfect
I could have discarded you could have discarded she could have discarded we could have discarded you could have discarded they could have discarded
V-ing perfect
I could have been discarding you could have been discarding she could have been discarding we could have been discarding you could have been discarding they could have been discarding
Negation
Simple form
I couldn't discard you couldn't discard she couldn't discard we couldn't discard you couldn't discard they couldn't discard
V-ing form
I couldn't be discarding you couldn't be discarding she couldn't be discarding we couldn't be discarding you couldn't be discarding they couldn't be discarding
Perfect
I couldn't have discarded you couldn't have discarded she couldn't have discarded we couldn't have discarded you couldn't have discarded they couldn't have discarded
V-ing perfect
I couldn't have been discarding you couldn't have been discarding she couldn't have been discarding we couldn't have been discarding you couldn't have been discarding they couldn't have been discarding
Interrogative form
Simple form
could I discard? could you discard? could she discard? could we discard? could you discard? could they discard?
V-ing form
could I be discarding? could you be discarding? could she be discarding? could we be discarding? could you be discarding? could they be discarding?
Perfect
could I have discarded? could you have discarded? could she have discarded? could we have discarded? could you have discarded? could they have discarded?
V-ing perfect
could I have been discarding? could you have been discarding? could she have been discarding? could we have been discarding? could you have been discarding? could they have been discarding?
Interro-negative form
Simple form
couldn't I discard? couldn't you discard? couldn't she discard? couldn't we discard? couldn't you discard? couldn't they discard?
V-ing form
couldn't I be discarding? couldn't you be discarding? couldn't she be discarding? couldn't we be discarding? couldn't you be discarding? couldn't they be discarding?
Perfect
couldn't I have discarded? couldn't you have discarded? couldn't she have discarded? couldn't we have discarded? couldn't you have discarded? couldn't they have discarded?
V-ing perfect
couldn't I have been discarding? couldn't you have been discarding? couldn't she have been discarding? couldn't we have been discarding? couldn't you have been discarding? couldn't they have been discarding?