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 couldn't trill you couldn't trill he couldn't trill we couldn't trill you couldn't trill they couldn't trill	I couldn't be trilling you couldn't be trilling he couldn't be trilling we couldn't be trilling you couldn't be trilling they couldn't be trilling
Perfect	V-ing perfect
I couldn't have trilled you couldn't have trilled he couldn't have trilled we couldn't have trilled you couldn't have trilled they couldn't have trilled	I couldn't have been trilling you couldn't have been trilling he couldn't have been trilling we couldn't have been trilling you couldn't have been trilling they couldn't 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
couldn't I trill? couldn't you trill? couldn't he trill? couldn't we trill? couldn't you trill? couldn't they trill?	couldn't I be trilling? couldn't you be trilling? couldn't he be trilling? couldn't we be trilling? couldn't you be trilling? couldn't they be trilling?
Perfect	V-ing perfect
couldn't I have trilled? couldn't you have trilled? couldn't he have trilled? couldn't we have trilled? couldn't you have trilled? couldn't they have trilled?	couldn't I have been trilling? couldn't you have been trilling? couldn't he have been trilling? couldn't we have been trilling? couldn't you have been trilling? couldn't they have been trilling?