A: I have too many ideas.<br/><br/>B: Is that a problem? <br/><br/>A: It is if you have to put them all in one article, and you can use only a thousand words.<br/><br/>B: A thousand? that sounds like a lot to me.<br/><br/>A: It isn't a lot, <u>not if</u> you want to describe the Navajo reservation. <br/><br/>I don't undersand what the underline 'not if' means.<br/><br/>It seems to have different meaning from 'if not'. <br/><br/>could someone tell me exactly what "not if' means?<br/><br/>thanks in advance.