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