Suppose if you anchor text with one keyword (ex: God) and some one searches for longtrail/phrase keywords that include the single word "god" (example: "who is god"). Then can the search results show your website for "who is god" in page one if your competitors have less backlinks, less SEO, missing keyword in some parts of the page (description, tittle, header, article ) but you do have it on all places. Meaning, can you still get extra traffic for longtrail/phrase keywords even if you used only one keyword for anchor text?