English verb conjugation
COULD KNURL

Regular verb: knurl - knurled - knurled

Affirmation

Simple form	V-ing form
I could knurl you could knurl he could knurl we could knurl you could knurl they could knurl	I could be knurling you could be knurling he could be knurling we could be knurling you could be knurling they could be knurling
Perfect	V-ing perfect
I could have knurled you could have knurled he could have knurled we could have knurled you could have knurled they could have knurled	I could have been knurling you could have been knurling he could have been knurling we could have been knurling you could have been knurling they could have been knurling

Negation

Simple form	V-ing form
I couldn't knurl you couldn't knurl he couldn't knurl we couldn't knurl you couldn't knurl they couldn't knurl	I couldn't be knurling you couldn't be knurling he couldn't be knurling we couldn't be knurling you couldn't be knurling they couldn't be knurling
Perfect	V-ing perfect
I couldn't have knurled you couldn't have knurled he couldn't have knurled we couldn't have knurled you couldn't have knurled they couldn't have knurled	I couldn't have been knurling you couldn't have been knurling he couldn't have been knurling we couldn't have been knurling you couldn't have been knurling they couldn't have been knurling

Interrogative form

Simple form	V-ing form
could I knurl? could you knurl? could he knurl? could we knurl? could you knurl? could they knurl?	could I be knurling? could you be knurling? could he be knurling? could we be knurling? could you be knurling? could they be knurling?
Perfect	V-ing perfect
could I have knurled? could you have knurled? could he have knurled? could we have knurled? could you have knurled? could they have knurled?	could I have been knurling? could you have been knurling? could he have been knurling? could we have been knurling? could you have been knurling? could they have been knurling?

Interro-negative form

Simple form	V-ing form
couldn't I knurl? couldn't you knurl? couldn't he knurl? couldn't we knurl? couldn't you knurl? couldn't they knurl?	couldn't I be knurling? couldn't you be knurling? couldn't he be knurling? couldn't we be knurling? couldn't you be knurling? couldn't they be knurling?
Perfect	V-ing perfect
couldn't I have knurled? couldn't you have knurled? couldn't he have knurled? couldn't we have knurled? couldn't you have knurled? couldn't they have knurled?	couldn't I have been knurling? couldn't you have been knurling? couldn't he have been knurling? couldn't we have been knurling? couldn't you have been knurling? couldn't they have been knurling?