could tail
Verbo regular: tail - tailed- tailed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could tail
you could tail
she could tail
we could tail
you could tail
they could tail 	I could be tailing
you could be tailing
she could be tailing
we could be tailing
you could be tailing
they could be tailing	I could have tailed
you could have tailed
she 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
she could have been tailing
we could have been tailing
you could have been tailing
they could have been tailing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't tail
you couldn't tail
she couldn't tail
we couldn't tail
you couldn't tail
they couldn't tail 	I couldn't be tailing
you couldn't be tailing
she couldn't be tailing
we couldn't be tailing
you couldn't be tailing
they couldn't be tailing	I couldn't have tailed
you couldn't have tailed
she couldn't have tailed
we couldn't have tailed
you couldn't have tailed
they couldn't have tailed	I couldn't have been tailing
you couldn't have been tailing
she couldn't have been tailing
we couldn't have been tailing
you couldn't have been tailing
they couldn't have been tailing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I tail?
could you tail?
could she tail?
could we tail?
could you tail?
could they tail? 	could I be tailing?
could you be tailing?
could she be tailing?
could we be tailing?
could you be tailing?
could they be tailing? 	could I have tailed?
could you have tailed?
could she 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 she have been tailing?
could we have been tailing?
could you have been tailing?
could they have been tailing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I tail?
couldn't you tail?
couldn't she tail?
couldn't we tail?
couldn't you tail?
couldn't they tail? 	couldn't I be tailing?
couldn't you be tailing?
couldn't she be tailing?
couldn't we be tailing?
couldn't you be tailing?
couldn't they be tailing? 	couldn't I have tailed?
couldn't you have tailed?
couldn't she have tailed?
couldn't we have tailed?
couldn't you have tailed?
couldn't they have tailed? 	couldn't I have been tailing?
couldn't you have been tailing?
couldn't she have been tailing?
couldn't we have been tailing?
couldn't you have been tailing?
couldn't they have been tailing?