Suggest please, what is the number of the expression "not only X<br/>but also Y"?<br/><br/>([Edited] Both X and Y are supposed to be either uncountable or<br/><br/>countable singular noun phrases.)<br/><br/>In other words, which of the following sentences is correct?<br/><br/>A) not only glass but also water <b>are</b> considered mineral<b>s</b><br/><br/>B) not only glass but also water <b>is</b> considered <b>a</b> mineral<b>_</b><br/><br/>Thanks in advance.<br/><br/>--<br/><br/>Victor