GCSE Coursework help needed please!

[Kaz]

Hi, I'm new here and in need of desperate help with GCSE coursework. This isn't for me but for my errant nephew who needs a swift kick but instead has to put up with his aunt trying to help :)

I know this probably isn't the place for this question and I apologise in advance if my topic needs moving elsewhere.

Ok. I don't know Shakespeare very well and I'm hoping someone here does. The essay question is:- When does Romeo and Juliet turn from a love story into a tragedy?

Many thanks to anyone who can help - I will appreciate it forever and when I've finished with this one, I will be sure to bother you with more questions :D

[Tdol]

The conventional model for a five act tragedy peaks in the third act, so when Romeo kills Tybalt thing get out of hand and fate determines the rest.