English verb conjugation
COULD TAIL

Regular verb: tail - tailed - tailed

Affirmation

Simple form	V-ing form
I could tail you could tail he could tail we could tail you could tail they could tail	I could be tailing you could be tailing he could be tailing we could be tailing you could be tailing they could be tailing
Perfect	V-ing perfect
I could have tailed you could have tailed he could have tailed we could have tailed you could have tailed they could have tailed	I could have been tailing you could have been tailing he could have been tailing we could have been tailing you could have been tailing they could have been tailing

Negation

Simple form	V-ing form
I could not tail you could not tail he could not tail we could not tail you could not tail they could not tail	I could not be tailing you could not be tailing he could not be tailing we could not be tailing you could not be tailing they could not be tailing
Perfect	V-ing perfect
I could not have tailed you could not have tailed he could not have tailed we could not have tailed you could not have tailed they could not have tailed	I could not have been tailing you could not have been tailing he could not have been tailing we could not have been tailing you could not have been tailing they could not have been tailing

Interrogative form

Simple form	V-ing form
could I tail? could you tail? could he tail? could we tail? could you tail? could they tail?	could I be tailing? could you be tailing? could he be tailing? could we be tailing? could you be tailing? could they be tailing?
Perfect	V-ing perfect
could I have tailed? could you have tailed? could he have tailed? could we have tailed? could you have tailed? could they have tailed?	could I have been tailing? could you have been tailing? could he have been tailing? could we have been tailing? could you have been tailing? could they have been tailing?

Interro-negative form

Simple form	V-ing form
could I not tail? could you not tail? could he not tail? could we not tail? could you not tail? could they not tail?	could I not be tailing? could you not be tailing? could he not be tailing? could we not be tailing? could you not be tailing? could they not be tailing?
Perfect	V-ing perfect
could I not have tailed? could you not have tailed? could he not have tailed? could we not have tailed? could you not have tailed? could they not have tailed?	could I not have been tailing? could you not have been tailing? could he not have been tailing? could we not have been tailing? could you not have been tailing? could they not have been tailing?