can concentrate
Verbo regular: concentrate - concentrated- concentrated

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

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I can't concentrate
you can't concentrate
he can't concentrate
we can't concentrate
you can't concentrate
they can't concentrate 	I can't be concentrating
you can't be concentrating
he can't be concentrating
we can't be concentrating
you can't be concentrating
they can't be concentrating	I can't have concentrated
you can't have concentrated
he can't have concentrated
we can't have concentrated
you can't have concentrated
they can't have concentrated	I can't have been concentrating
you can't have been concentrating
he can't have been concentrating
we can't have been concentrating
you can't have been concentrating
they can't have been concentrating	

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

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can't I concentrate?
can't you concentrate?
can't he concentrate?
can't we concentrate?
can't you concentrate?
can't they concentrate? 	can't I be concentrating?
can't you be concentrating?
can't he be concentrating?
can't we be concentrating?
can't you be concentrating?
can't they be concentrating? 	can't I have concentrated?
can't you have concentrated?
can't he have concentrated?
can't we have concentrated?
can't you have concentrated?
can't they have concentrated? 	can't I have been concentrating?
can't you have been concentrating?
can't he have been concentrating?
can't we have been concentrating?
can't you have been concentrating?
can't they have been concentrating?