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 could not purl you could not purl he could not purl we could not purl you could not purl they could not purl	I could not be purling you could not be purling he could not be purling we could not be purling you could not be purling they could not be purling
Perfect	V-ing perfect
I could not have purled you could not have purled he could not have purled we could not have purled you could not have purled they could not have purled	I could not have been purling you could not have been purling he could not have been purling we could not have been purling you could not have been purling they could not 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
could I not purl? could you not purl? could he not purl? could we not purl? could you not purl? could they not purl?	could I not be purling? could you not be purling? could he not be purling? could we not be purling? could you not be purling? could they not be purling?
Perfect	V-ing perfect
could I not have purled? could you not have purled? could he not have purled? could we not have purled? could you not have purled? could they not have purled?	could I not have been purling? could you not have been purling? could he not have been purling? could we not have been purling? could you not have been purling? could they not have been purling?