Of-Genitiv og Apostrofgenitiv i engelsk?!

Hej alle;)

Jeg skal aflevere en opgave i morgen, som lyder:
- Find alle genitivformerne i følgende tekst of gør rede for, hvorfor der er brugt henholdsvis of-genitiv og apostrofgenitiv. Forklar også, hvorfor apostroffen står, hvor den gør.

Last week’s papers had been full of stories about violence among teenagers, especially among boys. The front page story was about the death of a thirteen-year-old-boy, who had been walking in one of the dangerous areas of the city, and had been stabbed from behind by a member of a teenage gang. The next day the members of the gang maintained that they didn’t remember much of last night’s events, but they did remember that the owner of the pub where they had spent the evening had thrown them out. Afterwards they had gone to a friend of one of the gang members to have a few more drinks, and then they had continued their drinking at somebody else’s place – they remembered neither the name of the person nor the street where he lived, but they thought it was in the neighborhood of St. Paul’s. The fingerprints of one of the gang members were found on the knife that had been left in the young boy’s back, and the killer was sentenced to seven year’s imprisonment.
 

Jeg er på helt bar bund! Jeg har set en video om genitiv herinde, og googlet en del - men jeg forstår det stadig ikke!

Hjælp, hjælp! På forhånd tak:)