English verb conjugation
COULD TRILL

Regular verb: trill - trilled - trilled

Affirmation

Simple form	V-ing form
I could trill you could trill he could trill we could trill you could trill they could trill	I could be trilling you could be trilling he could be trilling we could be trilling you could be trilling they could be trilling
Perfect	V-ing perfect
I could have trilled you could have trilled he could have trilled we could have trilled you could have trilled they could have trilled	I could have been trilling you could have been trilling he could have been trilling we could have been trilling you could have been trilling they could have been trilling

Negation

Simple form	V-ing form
I could not trill you could not trill he could not trill we could not trill you could not trill they could not trill	I could not be trilling you could not be trilling he could not be trilling we could not be trilling you could not be trilling they could not be trilling
Perfect	V-ing perfect
I could not have trilled you could not have trilled he could not have trilled we could not have trilled you could not have trilled they could not have trilled	I could not have been trilling you could not have been trilling he could not have been trilling we could not have been trilling you could not have been trilling they could not have been trilling

Interrogative form

Simple form	V-ing form
could I trill? could you trill? could he trill? could we trill? could you trill? could they trill?	could I be trilling? could you be trilling? could he be trilling? could we be trilling? could you be trilling? could they be trilling?
Perfect	V-ing perfect
could I have trilled? could you have trilled? could he have trilled? could we have trilled? could you have trilled? could they have trilled?	could I have been trilling? could you have been trilling? could he have been trilling? could we have been trilling? could you have been trilling? could they have been trilling?

Interro-negative form

Simple form	V-ing form
could I not trill? could you not trill? could he not trill? could we not trill? could you not trill? could they not trill?	could I not be trilling? could you not be trilling? could he not be trilling? could we not be trilling? could you not be trilling? could they not be trilling?
Perfect	V-ing perfect
could I not have trilled? could you not have trilled? could he not have trilled? could we not have trilled? could you not have trilled? could they not have trilled?	could I not have been trilling? could you not have been trilling? could he not have been trilling? could we not have been trilling? could you not have been trilling? could they not have been trilling?