English verb conjugation
COULD ROLLER-SKATE

Regular verb: roller-skate - roller-skated - roller-skated

Affirmation

Simple form	V-ing form
I could roller-skate you could roller-skate he could roller-skate we could roller-skate you could roller-skate they could roller-skate	I could be roller-skating you could be roller-skating he could be roller-skating we could be roller-skating you could be roller-skating they could be roller-skating
Perfect	V-ing perfect
I could have roller-skated you could have roller-skated he could have roller-skated we could have roller-skated you could have roller-skated they could have roller-skated	I could have been roller-skating you could have been roller-skating he could have been roller-skating we could have been roller-skating you could have been roller-skating they could have been roller-skating

Negation

Simple form	V-ing form
I could not roller-skate you could not roller-skate he could not roller-skate we could not roller-skate you could not roller-skate they could not roller-skate	I could not be roller-skating you could not be roller-skating he could not be roller-skating we could not be roller-skating you could not be roller-skating they could not be roller-skating
Perfect	V-ing perfect
I could not have roller-skated you could not have roller-skated he could not have roller-skated we could not have roller-skated you could not have roller-skated they could not have roller-skated	I could not have been roller-skating you could not have been roller-skating he could not have been roller-skating we could not have been roller-skating you could not have been roller-skating they could not have been roller-skating

Interrogative form

Simple form	V-ing form
could I roller-skate? could you roller-skate? could he roller-skate? could we roller-skate? could you roller-skate? could they roller-skate?	could I be roller-skating? could you be roller-skating? could he be roller-skating? could we be roller-skating? could you be roller-skating? could they be roller-skating?
Perfect	V-ing perfect
could I have roller-skated? could you have roller-skated? could he have roller-skated? could we have roller-skated? could you have roller-skated? could they have roller-skated?	could I have been roller-skating? could you have been roller-skating? could he have been roller-skating? could we have been roller-skating? could you have been roller-skating? could they have been roller-skating?

Interro-negative form

Simple form	V-ing form
could I not roller-skate? could you not roller-skate? could he not roller-skate? could we not roller-skate? could you not roller-skate? could they not roller-skate?	could I not be roller-skating? could you not be roller-skating? could he not be roller-skating? could we not be roller-skating? could you not be roller-skating? could they not be roller-skating?
Perfect	V-ing perfect
could I not have roller-skated? could you not have roller-skated? could he not have roller-skated? could we not have roller-skated? could you not have roller-skated? could they not have roller-skated?	could I not have been roller-skating? could you not have been roller-skating? could he not have been roller-skating? could we not have been roller-skating? could you not have been roller-skating? could they not have been roller-skating?