English verb conjugation
COULD YELL

Regular verb: yell - yelled - yelled

Affirmation

Simple form	V-ing form
I could yell you could yell she could yell we could yell you could yell they could yell	I could be yelling you could be yelling she could be yelling we could be yelling you could be yelling they could be yelling
Perfect	V-ing perfect
I could have yelled you could have yelled she could have yelled we could have yelled you could have yelled they could have yelled	I could have been yelling you could have been yelling she could have been yelling we could have been yelling you could have been yelling they could have been yelling

Negation

Simple form	V-ing form
I couldn't yell you couldn't yell she couldn't yell we couldn't yell you couldn't yell they couldn't yell	I couldn't be yelling you couldn't be yelling she couldn't be yelling we couldn't be yelling you couldn't be yelling they couldn't be yelling
Perfect	V-ing perfect
I couldn't have yelled you couldn't have yelled she couldn't have yelled we couldn't have yelled you couldn't have yelled they couldn't have yelled	I couldn't have been yelling you couldn't have been yelling she couldn't have been yelling we couldn't have been yelling you couldn't have been yelling they couldn't have been yelling

Interrogative form

Simple form	V-ing form
could I yell? could you yell? could she yell? could we yell? could you yell? could they yell?	could I be yelling? could you be yelling? could she be yelling? could we be yelling? could you be yelling? could they be yelling?
Perfect	V-ing perfect
could I have yelled? could you have yelled? could she have yelled? could we have yelled? could you have yelled? could they have yelled?	could I have been yelling? could you have been yelling? could she have been yelling? could we have been yelling? could you have been yelling? could they have been yelling?

Interro-negative form

Simple form	V-ing form
couldn't I yell? couldn't you yell? couldn't she yell? couldn't we yell? couldn't you yell? couldn't they yell?	couldn't I be yelling? couldn't you be yelling? couldn't she be yelling? couldn't we be yelling? couldn't you be yelling? couldn't they be yelling?
Perfect	V-ing perfect
couldn't I have yelled? couldn't you have yelled? couldn't she have yelled? couldn't we have yelled? couldn't you have yelled? couldn't they have yelled?	couldn't I have been yelling? couldn't you have been yelling? couldn't she have been yelling? couldn't we have been yelling? couldn't you have been yelling? couldn't they have been yelling?