English verb conjugation
COULD PURL

Regular verb: purl - purled - purled

Affirmation

Simple form	V-ing form
I could purl you could purl he could purl we could purl you could purl they could purl	I could be purling you could be purling he could be purling we could be purling you could be purling they could be purling
Perfect	V-ing perfect
I could have purled you could have purled he could have purled we could have purled you could have purled they could have purled	I could have been purling you could have been purling he could have been purling we could have been purling you could have been purling they could have been purling

Negation

Simple form	V-ing form
I couldn't purl you couldn't purl he couldn't purl we couldn't purl you couldn't purl they couldn't purl	I couldn't be purling you couldn't be purling he couldn't be purling we couldn't be purling you couldn't be purling they couldn't be purling
Perfect	V-ing perfect
I couldn't have purled you couldn't have purled he couldn't have purled we couldn't have purled you couldn't have purled they couldn't have purled	I couldn't have been purling you couldn't have been purling he couldn't have been purling we couldn't have been purling you couldn't have been purling they couldn't have been purling

Interrogative form

Simple form	V-ing form
could I purl? could you purl? could he purl? could we purl? could you purl? could they purl?	could I be purling? could you be purling? could he be purling? could we be purling? could you be purling? could they be purling?
Perfect	V-ing perfect
could I have purled? could you have purled? could he have purled? could we have purled? could you have purled? could they have purled?	could I have been purling? could you have been purling? could he have been purling? could we have been purling? could you have been purling? could they have been purling?

Interro-negative form

Simple form	V-ing form
couldn't I purl? couldn't you purl? couldn't he purl? couldn't we purl? couldn't you purl? couldn't they purl?	couldn't I be purling? couldn't you be purling? couldn't he be purling? couldn't we be purling? couldn't you be purling? couldn't they be purling?
Perfect	V-ing perfect
couldn't I have purled? couldn't you have purled? couldn't he have purled? couldn't we have purled? couldn't you have purled? couldn't they have purled?	couldn't I have been purling? couldn't you have been purling? couldn't he have been purling? couldn't we have been purling? couldn't you have been purling? couldn't they have been purling?