sql track on object

 Hi All,

Is there anyway we can track the sql's that used a particular object for the past 3 days,

i used this below statement  to pull sqlid ,but i also need the sql text to be included,i tried with some joins but i get various error messages,

select distinct sql_id,timestamp from dba_hist_sql_plan where timestamp > sysdate -3;

also we need to drop columns in table which are not used ,how do we check unused columns

version: 11.2.0.1

-Thanks