I could operate you could operate he could operate we could operate you could operate they could operate
Forma com V-ing
I could be operating you could be operating he could be operating we could be operating you could be operating they could be operating
Perfeito
I could have operated you could have operated he could have operated we could have operated you could have operated they could have operated
Perfeito com V-ing
I could have been operating you could have been operating he could have been operating we could have been operating you could have been operating they could have been operating
Negação
Forma simple
I couldn't operate you couldn't operate he couldn't operate we couldn't operate you couldn't operate they couldn't operate
Forma com V-ing
I couldn't be operating you couldn't be operating he couldn't be operating we couldn't be operating you couldn't be operating they couldn't be operating
Perfeito
I couldn't have operated you couldn't have operated he couldn't have operated we couldn't have operated you couldn't have operated they couldn't have operated
Perfeito com V-ing
I couldn't have been operating you couldn't have been operating he couldn't have been operating we couldn't have been operating you couldn't have been operating they couldn't have been operating
Forma interrogativa
Forma simple
could I operate? could you operate? could he operate? could we operate? could you operate? could they operate?
Forma com V-ing
could I be operating? could you be operating? could he be operating? could we be operating? could you be operating? could they be operating?
Perfeito
could I have operated? could you have operated? could he have operated? could we have operated? could you have operated? could they have operated?
Perfeito com V-ing
could I have been operating? could you have been operating? could he have been operating? could we have been operating? could you have been operating? could they have been operating?
Forma interro-Negação
Forma simple
couldn't I operate? couldn't you operate? couldn't he operate? couldn't we operate? couldn't you operate? couldn't they operate?
Forma com V-ing
couldn't I be operating? couldn't you be operating? couldn't he be operating? couldn't we be operating? couldn't you be operating? couldn't they be operating?
Perfeito
couldn't I have operated? couldn't you have operated? couldn't he have operated? couldn't we have operated? couldn't you have operated? couldn't they have operated?
Perfeito com V-ing
couldn't I have been operating? couldn't you have been operating? couldn't he have been operating? couldn't we have been operating? couldn't you have been operating? couldn't they have been operating?