Conjugación del verbo inglés
CAN WARN

Verbo regular: warn - warned - warned

Afirmación

Forma simple	Forma con V-ing
I can warn you can warn she can warn we can warn you can warn they can warn	I can be warning you can be warning she can be warning we can be warning you can be warning they can be warning
Perfecto	Perfecto con V-ing
I can have warned you can have warned she can have warned we can have warned you can have warned they can have warned	I can have been warning you can have been warning she can have been warning we can have been warning you can have been warning they can have been warning

Negación

Forma simple	Forma con V-ing
I cannot warn you cannot warn she cannot warn we cannot warn you cannot warn they cannot warn	I cannot be warning you cannot be warning she cannot be warning we cannot be warning you cannot be warning they cannot be warning
Perfecto	Perfecto con V-ing
I cannot have warned you cannot have warned she cannot have warned we cannot have warned you cannot have warned they cannot have warned	I cannot have been warning you cannot have been warning she cannot have been warning we cannot have been warning you cannot have been warning they cannot have been warning

Forma interrogativa

Forma simple	Forma con V-ing
can I warn? can you warn? can she warn? can we warn? can you warn? can they warn?	can I be warning? can you be warning? can she be warning? can we be warning? can you be warning? can they be warning?
Perfecto	Perfecto con V-ing
can I have warned? can you have warned? can she have warned? can we have warned? can you have warned? can they have warned?	can I have been warning? can you have been warning? can she have been warning? can we have been warning? can you have been warning? can they have been warning?

Forma interro-negativa

Forma simple	Forma con V-ing
can I not warn? can you not warn? can she not warn? can we not warn? can you not warn? can they not warn?	can I not be warning? can you not be warning? can she not be warning? can we not be warning? can you not be warning? can they not be warning?
Perfecto	Perfecto con V-ing
can I not have warned? can you not have warned? can she not have warned? can we not have warned? can you not have warned? can they not have warned?	can I not have been warning? can you not have been warning? can she not have been warning? can we not have been warning? can you not have been warning? can they not have been warning?