the first one is "gastaron" which means spent, this makes the sentence look like Ellos gastaron mucho dinero, this means they spent too much money
the second one is "escribio" which means he wrote, this makes the sentence look like Juan escribio un cuento, this means Juan wrote a story
the third one is "compre" which means I bought, this makes the sentence look like Anoche yo compre una chaqueta nueva, this means Last night I bought a new jacket
Hope this helps
