Conjugação do verbo inglês
COULD OBSERVE

Verbo regular: observe - observed - observed

Afirmação

Forma simple	Forma com V-ing
I could observe you could observe he could observe we could observe you could observe they could observe	I could be observing you could be observing he could be observing we could be observing you could be observing they could be observing
Perfeito	Perfeito com V-ing
I could have observed you could have observed he could have observed we could have observed you could have observed they could have observed	I could have been observing you could have been observing he could have been observing we could have been observing you could have been observing they could have been observing

Negação

Forma simple	Forma com V-ing
I could not observe you could not observe he could not observe we could not observe you could not observe they could not observe	I could not be observing you could not be observing he could not be observing we could not be observing you could not be observing they could not be observing
Perfeito	Perfeito com V-ing
I could not have observed you could not have observed he could not have observed we could not have observed you could not have observed they could not have observed	I could not have been observing you could not have been observing he could not have been observing we could not have been observing you could not have been observing they could not have been observing

Forma interrogativa

Forma simple	Forma com V-ing
could I observe? could you observe? could he observe? could we observe? could you observe? could they observe?	could I be observing? could you be observing? could he be observing? could we be observing? could you be observing? could they be observing?
Perfeito	Perfeito com V-ing
could I have observed? could you have observed? could he have observed? could we have observed? could you have observed? could they have observed?	could I have been observing? could you have been observing? could he have been observing? could we have been observing? could you have been observing? could they have been observing?

Forma interro-Negação

Forma simple	Forma com V-ing
could I not observe? could you not observe? could he not observe? could we not observe? could you not observe? could they not observe?	could I not be observing? could you not be observing? could he not be observing? could we not be observing? could you not be observing? could they not be observing?
Perfeito	Perfeito com V-ing
could I not have observed? could you not have observed? could he not have observed? could we not have observed? could you not have observed? could they not have observed?	could I not have been observing? could you not have been observing? could he not have been observing? could we not have been observing? could you not have been observing? could they not have been observing?