Past Simple vs. Past Perfect

Source: http://e.foi.hr/engwiki/index.php/Past_Simple_vs._Past_Perfect_1a (Goran Grgić, G12 & Antonela Čižmešija)

Source:  http://e.foi.hr/engwiki/index.php/Past_Simple_vs._Past_Perfect_3 (Lucija Kožar)