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