English verb conjugation
COULD MAIL

Regular verb: mail - mailed - mailed

Affirmation

Simple form	V-ing form
I could mail you could mail he could mail we could mail you could mail they could mail	I could be mailing you could be mailing he could be mailing we could be mailing you could be mailing they could be mailing
Perfect	V-ing perfect
I could have mailed you could have mailed he could have mailed we could have mailed you could have mailed they could have mailed	I could have been mailing you could have been mailing he could have been mailing we could have been mailing you could have been mailing they could have been mailing

Negation

Simple form	V-ing form
I couldn't mail you couldn't mail he couldn't mail we couldn't mail you couldn't mail they couldn't mail	I couldn't be mailing you couldn't be mailing he couldn't be mailing we couldn't be mailing you couldn't be mailing they couldn't be mailing
Perfect	V-ing perfect
I couldn't have mailed you couldn't have mailed he couldn't have mailed we couldn't have mailed you couldn't have mailed they couldn't have mailed	I couldn't have been mailing you couldn't have been mailing he couldn't have been mailing we couldn't have been mailing you couldn't have been mailing they couldn't have been mailing

Interrogative form

Simple form	V-ing form
could I mail? could you mail? could he mail? could we mail? could you mail? could they mail?	could I be mailing? could you be mailing? could he be mailing? could we be mailing? could you be mailing? could they be mailing?
Perfect	V-ing perfect
could I have mailed? could you have mailed? could he have mailed? could we have mailed? could you have mailed? could they have mailed?	could I have been mailing? could you have been mailing? could he have been mailing? could we have been mailing? could you have been mailing? could they have been mailing?

Interro-negative form

Simple form	V-ing form
couldn't I mail? couldn't you mail? couldn't he mail? couldn't we mail? couldn't you mail? couldn't they mail?	couldn't I be mailing? couldn't you be mailing? couldn't he be mailing? couldn't we be mailing? couldn't you be mailing? couldn't they be mailing?
Perfect	V-ing perfect
couldn't I have mailed? couldn't you have mailed? couldn't he have mailed? couldn't we have mailed? couldn't you have mailed? couldn't they have mailed?	couldn't I have been mailing? couldn't you have been mailing? couldn't he have been mailing? couldn't we have been mailing? couldn't you have been mailing? couldn't they have been mailing?