I could stir you could stir he could stir we could stir you could stir they could stir
V-ing form
I could be stirring you could be stirring he could be stirring we could be stirring you could be stirring they could be stirring
Perfect
I could have stirred you could have stirred he could have stirred we could have stirred you could have stirred they could have stirred
V-ing perfect
I could have been stirring you could have been stirring he could have been stirring we could have been stirring you could have been stirring they could have been stirring
Negation
Simple form
I couldn't stir you couldn't stir he couldn't stir we couldn't stir you couldn't stir they couldn't stir
V-ing form
I couldn't be stirring you couldn't be stirring he couldn't be stirring we couldn't be stirring you couldn't be stirring they couldn't be stirring
Perfect
I couldn't have stirred you couldn't have stirred he couldn't have stirred we couldn't have stirred you couldn't have stirred they couldn't have stirred
V-ing perfect
I couldn't have been stirring you couldn't have been stirring he couldn't have been stirring we couldn't have been stirring you couldn't have been stirring they couldn't have been stirring
Interrogative form
Simple form
could I stir? could you stir? could he stir? could we stir? could you stir? could they stir?
V-ing form
could I be stirring? could you be stirring? could he be stirring? could we be stirring? could you be stirring? could they be stirring?
Perfect
could I have stirred? could you have stirred? could he have stirred? could we have stirred? could you have stirred? could they have stirred?
V-ing perfect
could I have been stirring? could you have been stirring? could he have been stirring? could we have been stirring? could you have been stirring? could they have been stirring?
Interro-negative form
Simple form
couldn't I stir? couldn't you stir? couldn't he stir? couldn't we stir? couldn't you stir? couldn't they stir?
V-ing form
couldn't I be stirring? couldn't you be stirring? couldn't he be stirring? couldn't we be stirring? couldn't you be stirring? couldn't they be stirring?
Perfect
couldn't I have stirred? couldn't you have stirred? couldn't he have stirred? couldn't we have stirred? couldn't you have stirred? couldn't they have stirred?
V-ing perfect
couldn't I have been stirring? couldn't you have been stirring? couldn't he have been stirring? couldn't we have been stirring? couldn't you have been stirring? couldn't they have been stirring?