English verb conjugation
COULD FLEX

Regular verb: flex - flexed - flexed

Affirmation

Simple form	V-ing form
I could flex you could flex he could flex we could flex you could flex they could flex	I could be flexing you could be flexing he could be flexing we could be flexing you could be flexing they could be flexing
Perfect	V-ing perfect
I could have flexed you could have flexed he could have flexed we could have flexed you could have flexed they could have flexed	I could have been flexing you could have been flexing he could have been flexing we could have been flexing you could have been flexing they could have been flexing

Negation

Simple form	V-ing form
I couldn't flex you couldn't flex he couldn't flex we couldn't flex you couldn't flex they couldn't flex	I couldn't be flexing you couldn't be flexing he couldn't be flexing we couldn't be flexing you couldn't be flexing they couldn't be flexing
Perfect	V-ing perfect
I couldn't have flexed you couldn't have flexed he couldn't have flexed we couldn't have flexed you couldn't have flexed they couldn't have flexed	I couldn't have been flexing you couldn't have been flexing he couldn't have been flexing we couldn't have been flexing you couldn't have been flexing they couldn't have been flexing

Interrogative form

Simple form	V-ing form
could I flex? could you flex? could he flex? could we flex? could you flex? could they flex?	could I be flexing? could you be flexing? could he be flexing? could we be flexing? could you be flexing? could they be flexing?
Perfect	V-ing perfect
could I have flexed? could you have flexed? could he have flexed? could we have flexed? could you have flexed? could they have flexed?	could I have been flexing? could you have been flexing? could he have been flexing? could we have been flexing? could you have been flexing? could they have been flexing?

Interro-negative form

Simple form	V-ing form
couldn't I flex? couldn't you flex? couldn't he flex? couldn't we flex? couldn't you flex? couldn't they flex?	couldn't I be flexing? couldn't you be flexing? couldn't he be flexing? couldn't we be flexing? couldn't you be flexing? couldn't they be flexing?
Perfect	V-ing perfect
couldn't I have flexed? couldn't you have flexed? couldn't he have flexed? couldn't we have flexed? couldn't you have flexed? couldn't they have flexed?	couldn't I have been flexing? couldn't you have been flexing? couldn't he have been flexing? couldn't we have been flexing? couldn't you have been flexing? couldn't they have been flexing?