A Brooklyn teenager who went on a torrid two-week assault-spree last year was sentenced to 15 years in prison yesterday after pleading guilty. Eric Ferguson, 19, was linked to six separate attacks during May and June 2008. Among his victims were two Chinese deliverymen (one of whom was stabbed) and 62-year-old nun and Catholic school teacher Patricia McGowan, whose car and purse were stolen, and whose face was left an unholy mess: "Her left eye was blackened and bloodshot, and her left cheek was swollen and purple from her eye to her jaw."