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 couldn't observe you couldn't observe he couldn't observe we couldn't observe you couldn't observe they couldn't observe	I couldn't be observing you couldn't be observing he couldn't be observing we couldn't be observing you couldn't be observing they couldn't be observing
Perfeito	Perfeito com V-ing
I couldn't have observed you couldn't have observed he couldn't have observed we couldn't have observed you couldn't have observed they couldn't have observed	I couldn't have been observing you couldn't have been observing he couldn't have been observing we couldn't have been observing you couldn't have been observing they couldn't 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
couldn't I observe? couldn't you observe? couldn't he observe? couldn't we observe? couldn't you observe? couldn't they observe?	couldn't I be observing? couldn't you be observing? couldn't he be observing? couldn't we be observing? couldn't you be observing? couldn't they be observing?
Perfeito	Perfeito com V-ing
couldn't I have observed? couldn't you have observed? couldn't he have observed? couldn't we have observed? couldn't you have observed? couldn't they have observed?	couldn't I have been observing? couldn't you have been observing? couldn't he have been observing? couldn't we have been observing? couldn't you have been observing? couldn't they have been observing?