<?php

    $string = "one and two and three and four and five";
    $stringArray = explode(" and ", $string);
    $stringArrayItemCount = count($stringArray);
    $stringArrayLastItem = $stringArray[$stringArrayItemCount-1];
    unset($stringArray[$stringArrayItemCount-1]);
    $stringArray = array(implode(" and ",$stringArray),$stringArrayLastItem);
    
    print_r($stringArray);