I think the distinction between queries and keywords is important. A keyword is the flat, literal, lowest-common-denominator word that you want as much commercial intent in it as possible. A search query is the actual phrase that the user puts in the search box. More often than not search queries are absurd. The keywords you select are just as much about what queries you don’t want your ad to show up for, as the queries that you do want your ad to show for.

As seen above, search queries of all types are swimming through a stream and you lure the ones you want your ad to show up for by using keywords, match types and negatives.