I could thin you could thin he could thin we could thin you could thin they could thin
V-ing form
I could be thinning you could be thinning he could be thinning we could be thinning you could be thinning they could be thinning
Perfect
I could have thinned you could have thinned he could have thinned we could have thinned you could have thinned they could have thinned
V-ing perfect
I could have been thinning you could have been thinning he could have been thinning we could have been thinning you could have been thinning they could have been thinning
Negation
Simple form
I could not thin you could not thin he could not thin we could not thin you could not thin they could not thin
V-ing form
I could not be thinning you could not be thinning he could not be thinning we could not be thinning you could not be thinning they could not be thinning
Perfect
I could not have thinned you could not have thinned he could not have thinned we could not have thinned you could not have thinned they could not have thinned
V-ing perfect
I could not have been thinning you could not have been thinning he could not have been thinning we could not have been thinning you could not have been thinning they could not have been thinning
Interrogative form
Simple form
could I thin? could you thin? could he thin? could we thin? could you thin? could they thin?
V-ing form
could I be thinning? could you be thinning? could he be thinning? could we be thinning? could you be thinning? could they be thinning?
Perfect
could I have thinned? could you have thinned? could he have thinned? could we have thinned? could you have thinned? could they have thinned?
V-ing perfect
could I have been thinning? could you have been thinning? could he have been thinning? could we have been thinning? could you have been thinning? could they have been thinning?
Interro-negative form
Simple form
could I not thin? could you not thin? could he not thin? could we not thin? could you not thin? could they not thin?
V-ing form
could I not be thinning? could you not be thinning? could he not be thinning? could we not be thinning? could you not be thinning? could they not be thinning?
Perfect
could I not have thinned? could you not have thinned? could he not have thinned? could we not have thinned? could you not have thinned? could they not have thinned?
V-ing perfect
could I not have been thinning? could you not have been thinning? could he not have been thinning? could we not have been thinning? could you not have been thinning? could they not have been thinning?