Not completing essay?

<p>I wasn't able to finish my essay...
Last time I did it fine and received 12, but this time,
since I wasn't expecting that kind of topic at all,
I spent too much time thinking about examples in vain.
Yes, I admit, the examples I used were LAME.
In addition, when the time was out,
I just finished 1st sentence of conclusion paragraph.
So, how much effect will that incomplete essay have on my writing score
if writing score with 12 essay would be 670?</p>

<p>p.s. I still can't believe that I wasn't able to think about those two books!!! :@</p>