Verified answer

--I don't know. --I don't know, either. [tampoco]

Either your work improves or you're fired. [o...o]

You can have either tea or coffee. [o...o]

Flowers were growing on either side of the path. [ambos]

Either one would be suitable. [cualquiera de los dos]

She doesn't want either of them. [ninguno de los dos]

He neither knows nor cares. [ni...ni]

Neither of them were here. [ni el uno ni el otro]

Neither proposal was accepted. [ninguna de las dos]

--I can't swim. --Neither can I. [tampoco]