I could retry you could retry he could retry we could retry you could retry they could retry
V-ing form
I could be retrying you could be retrying he could be retrying we could be retrying you could be retrying they could be retrying
Perfect
I could have retried you could have retried he could have retried we could have retried you could have retried they could have retried
V-ing perfect
I could have been retrying you could have been retrying he could have been retrying we could have been retrying you could have been retrying they could have been retrying
Negation
Simple form
I couldn't retry you couldn't retry he couldn't retry we couldn't retry you couldn't retry they couldn't retry
V-ing form
I couldn't be retrying you couldn't be retrying he couldn't be retrying we couldn't be retrying you couldn't be retrying they couldn't be retrying
Perfect
I couldn't have retried you couldn't have retried he couldn't have retried we couldn't have retried you couldn't have retried they couldn't have retried
V-ing perfect
I couldn't have been retrying you couldn't have been retrying he couldn't have been retrying we couldn't have been retrying you couldn't have been retrying they couldn't have been retrying
Interrogative form
Simple form
could I retry? could you retry? could he retry? could we retry? could you retry? could they retry?
V-ing form
could I be retrying? could you be retrying? could he be retrying? could we be retrying? could you be retrying? could they be retrying?
Perfect
could I have retried? could you have retried? could he have retried? could we have retried? could you have retried? could they have retried?
V-ing perfect
could I have been retrying? could you have been retrying? could he have been retrying? could we have been retrying? could you have been retrying? could they have been retrying?
Interro-negative form
Simple form
couldn't I retry? couldn't you retry? couldn't he retry? couldn't we retry? couldn't you retry? couldn't they retry?
V-ing form
couldn't I be retrying? couldn't you be retrying? couldn't he be retrying? couldn't we be retrying? couldn't you be retrying? couldn't they be retrying?
Perfect
couldn't I have retried? couldn't you have retried? couldn't he have retried? couldn't we have retried? couldn't you have retried? couldn't they have retried?
V-ing perfect
couldn't I have been retrying? couldn't you have been retrying? couldn't he have been retrying? couldn't we have been retrying? couldn't you have been retrying? couldn't they have been retrying?