English verb conjugation
COULD TRAIL

Regular verb: trail - trailed - trailed

Affirmation

Simple form	V-ing form
I could trail you could trail he could trail we could trail you could trail they could trail	I could be trailing you could be trailing he could be trailing we could be trailing you could be trailing they could be trailing
Perfect	V-ing perfect
I could have trailed you could have trailed he could have trailed we could have trailed you could have trailed they could have trailed	I could have been trailing you could have been trailing he could have been trailing we could have been trailing you could have been trailing they could have been trailing

Negation

Simple form	V-ing form
I could not trail you could not trail he could not trail we could not trail you could not trail they could not trail	I could not be trailing you could not be trailing he could not be trailing we could not be trailing you could not be trailing they could not be trailing
Perfect	V-ing perfect
I could not have trailed you could not have trailed he could not have trailed we could not have trailed you could not have trailed they could not have trailed	I could not have been trailing you could not have been trailing he could not have been trailing we could not have been trailing you could not have been trailing they could not have been trailing

Interrogative form

Simple form	V-ing form
could I trail? could you trail? could he trail? could we trail? could you trail? could they trail?	could I be trailing? could you be trailing? could he be trailing? could we be trailing? could you be trailing? could they be trailing?
Perfect	V-ing perfect
could I have trailed? could you have trailed? could he have trailed? could we have trailed? could you have trailed? could they have trailed?	could I have been trailing? could you have been trailing? could he have been trailing? could we have been trailing? could you have been trailing? could they have been trailing?

Interro-negative form

Simple form	V-ing form
could I not trail? could you not trail? could he not trail? could we not trail? could you not trail? could they not trail?	could I not be trailing? could you not be trailing? could he not be trailing? could we not be trailing? could you not be trailing? could they not be trailing?
Perfect	V-ing perfect
could I not have trailed? could you not have trailed? could he not have trailed? could we not have trailed? could you not have trailed? could they not have trailed?	could I not have been trailing? could you not have been trailing? could he not have been trailing? could we not have been trailing? could you not have been trailing? could they not have been trailing?