Conjugación del verbo inglés
COULD CONCENTRATE

Verbo regular: concentrate - concentrated - concentrated

Afirmación

Forma simple	Forma con V-ing
I could concentrate you could concentrate he could concentrate we could concentrate you could concentrate they could concentrate	I could be concentrating you could be concentrating he could be concentrating we could be concentrating you could be concentrating they could be concentrating
Perfecto	Perfecto con V-ing
I could have concentrated you could have concentrated he could have concentrated we could have concentrated you could have concentrated they could have concentrated	I could have been concentrating you could have been concentrating he could have been concentrating we could have been concentrating you could have been concentrating they could have been concentrating

Negación

Forma simple	Forma con V-ing
I could not concentrate you could not concentrate he could not concentrate we could not concentrate you could not concentrate they could not concentrate	I could not be concentrating you could not be concentrating he could not be concentrating we could not be concentrating you could not be concentrating they could not be concentrating
Perfecto	Perfecto con V-ing
I could not have concentrated you could not have concentrated he could not have concentrated we could not have concentrated you could not have concentrated they could not have concentrated	I could not have been concentrating you could not have been concentrating he could not have been concentrating we could not have been concentrating you could not have been concentrating they could not have been concentrating

Forma interrogativa

Forma simple	Forma con V-ing
could I concentrate? could you concentrate? could he concentrate? could we concentrate? could you concentrate? could they concentrate?	could I be concentrating? could you be concentrating? could he be concentrating? could we be concentrating? could you be concentrating? could they be concentrating?
Perfecto	Perfecto con V-ing
could I have concentrated? could you have concentrated? could he have concentrated? could we have concentrated? could you have concentrated? could they have concentrated?	could I have been concentrating? could you have been concentrating? could he have been concentrating? could we have been concentrating? could you have been concentrating? could they have been concentrating?

Forma interro-negativa

Forma simple	Forma con V-ing
could I not concentrate? could you not concentrate? could he not concentrate? could we not concentrate? could you not concentrate? could they not concentrate?	could I not be concentrating? could you not be concentrating? could he not be concentrating? could we not be concentrating? could you not be concentrating? could they not be concentrating?
Perfecto	Perfecto con V-ing
could I not have concentrated? could you not have concentrated? could he not have concentrated? could we not have concentrated? could you not have concentrated? could they not have concentrated?	could I not have been concentrating? could you not have been concentrating? could he not have been concentrating? could we not have been concentrating? could you not have been concentrating? could they not have been concentrating?