#!/bin/bash s='id first_name last_name age address telephone item1 tax1 item2 tax2 item3 tax3' awk '{for (i=7; i<NF; i+=2) print $1, $2, $3, $4, $5, $6, $i, $(i+1)}' <<< "$s"
Standard input is empty
id first_name last_name age address telephone item1 tax1 id first_name last_name age address telephone item2 tax2 id first_name last_name age address telephone item3 tax3