English verb conjugation
COULD PERSEVERE

Regular verb: persevere - persevered - persevered

Affirmation

Simple form	V-ing form
I could persevere you could persevere he could persevere we could persevere you could persevere they could persevere	I could be persevering you could be persevering he could be persevering we could be persevering you could be persevering they could be persevering
Perfect	V-ing perfect
I could have persevered you could have persevered he could have persevered we could have persevered you could have persevered they could have persevered	I could have been persevering you could have been persevering he could have been persevering we could have been persevering you could have been persevering they could have been persevering

Negation

Simple form	V-ing form
I couldn't persevere you couldn't persevere he couldn't persevere we couldn't persevere you couldn't persevere they couldn't persevere	I couldn't be persevering you couldn't be persevering he couldn't be persevering we couldn't be persevering you couldn't be persevering they couldn't be persevering
Perfect	V-ing perfect
I couldn't have persevered you couldn't have persevered he couldn't have persevered we couldn't have persevered you couldn't have persevered they couldn't have persevered	I couldn't have been persevering you couldn't have been persevering he couldn't have been persevering we couldn't have been persevering you couldn't have been persevering they couldn't have been persevering

Interrogative form

Simple form	V-ing form
could I persevere? could you persevere? could he persevere? could we persevere? could you persevere? could they persevere?	could I be persevering? could you be persevering? could he be persevering? could we be persevering? could you be persevering? could they be persevering?
Perfect	V-ing perfect
could I have persevered? could you have persevered? could he have persevered? could we have persevered? could you have persevered? could they have persevered?	could I have been persevering? could you have been persevering? could he have been persevering? could we have been persevering? could you have been persevering? could they have been persevering?

Interro-negative form

Simple form	V-ing form
couldn't I persevere? couldn't you persevere? couldn't he persevere? couldn't we persevere? couldn't you persevere? couldn't they persevere?	couldn't I be persevering? couldn't you be persevering? couldn't he be persevering? couldn't we be persevering? couldn't you be persevering? couldn't they be persevering?
Perfect	V-ing perfect
couldn't I have persevered? couldn't you have persevered? couldn't he have persevered? couldn't we have persevered? couldn't you have persevered? couldn't they have persevered?	couldn't I have been persevering? couldn't you have been persevering? couldn't he have been persevering? couldn't we have been persevering? couldn't you have been persevering? couldn't they have been persevering?