could derail
Regular verb: derail - derailed- derailed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could derail
you could derail
he could derail
we could derail
you could derail
they could derail 	I could be derailing
you could be derailing
he could be derailing
we could be derailing
you could be derailing
they could be derailing	I could have derailed
you could have derailed
he could have derailed
we could have derailed
you could have derailed
they could have derailed	I could have been derailing
you could have been derailing
he could have been derailing
we could have been derailing
you could have been derailing
they could have been derailing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not derail
you could not derail
he could not derail
we could not derail
you could not derail
they could not derail 	I could not be derailing
you could not be derailing
he could not be derailing
we could not be derailing
you could not be derailing
they could not be derailing	I could not have derailed
you could not have derailed
he could not have derailed
we could not have derailed
you could not have derailed
they could not have derailed	I could not have been derailing
you could not have been derailing
he could not have been derailing
we could not have been derailing
you could not have been derailing
they could not have been derailing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I derail?
could you derail?
could he derail?
could we derail?
could you derail?
could they derail? 	could I be derailing?
could you be derailing?
could he be derailing?
could we be derailing?
could you be derailing?
could they be derailing? 	could I have derailed?
could you have derailed?
could he have derailed?
could we have derailed?
could you have derailed?
could they have derailed? 	could I have been derailing?
could you have been derailing?
could he have been derailing?
could we have been derailing?
could you have been derailing?
could they have been derailing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not derail?
could you not derail?
could he not derail?
could we not derail?
could you not derail?
could they not derail? 	could I not be derailing?
could you not be derailing?
could he not be derailing?
could we not be derailing?
could you not be derailing?
could they not be derailing? 	could I not have derailed?
could you not have derailed?
could he not have derailed?
could we not have derailed?
could you not have derailed?
could they not have derailed? 	could I not have been derailing?
could you not have been derailing?
could he not have been derailing?
could we not have been derailing?
could you not have been derailing?
could they not have been derailing?