OG 30(存货处理)中一句话的结构

 The new tax law allowed corporations to deduct the  cost of the product donated plus half the difference between cost and fair market selling price, with the proviso that deductions cannot exceed twice cost.

这句话到了plus后面就完全不知道怎么回事了.请帮忙分析一下...

哈哈,我刚做完这篇文章.我的理解是:新税法允许公司扣除公司捐赠的产品的成本加上市场上销售价格与成本之间差异的一半,但是还有一个限制:这个扣除不能超过成本的2倍.

也就是说,允许公司扣除的款项=公司捐赠的产品的成本+1/2*(市场上销售价格与成本之间差异)

不知道这个理解怎么样.

我也是这么理解的,但能不能分析一下这句话的具体结构啊

我是说句子成分

 The new tax law
                    allowed
                    corporations
                    to deduct the  cost of the product donated (plus half the difference between cost and fair market

       主语            谓语        宾语                      宾补                                                  超长的介词短语修饰cost

selling price), with the proviso that deductions cannot exceed twice cost.

我刚查了一下字典, 我想plus在这里应该是一个介词.