The match statement is used in route-maps and policy-maps in IOS to define criteria that a packet must meet in order to be classified as part of the permit or deny action of a route-map statement.  Route-maps can be roughly compared to an IF… THEN clause in programming.  Some match statements can have multiple conditions, like: [more]

match ip dscp af31 af32 af33

In which case each condition is OR’d with the one before it.  If any condition is true (in the above statement af31 af32 af33 are all possible DSCP values that an IP packet might have), then the match is true.  The other scenario is having multiple match statements:

match ip dscp af31
match ip dscp af32

In this case both statements have to be true for the packet to be classified in the given route-map entry.  In this case an IP packet could never be both af31 AND af32, so the route-map (or policy-map) will never match anything.