Cost Exceed Half Difference Fair Market Selling Deduct

意群训练： 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.

标志： 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 )/.

译文： 新税法 允许 各家公司减去被捐献产品的成本 ，再减去 (在 成本与 公平市场价格之间 的）差值的一半 ，/其限制性条款（是 减免 不可超过 成本的两倍 ）/。

解释： 句子的结构虽然不算难，但是其意思却很难理解对。尤其是deduct the cost of the product donated plus half the difference （between cost and fair market selling price）一句中居然出现了肯定与否定（正与负的）的四则运算：deduct A plus B不是指减去A然后加上B，而是指减去A再减去B，即S-(A+B)=S-A-B。作为本句的B的half the difference (between cost and fair market selling price）实际上指的是利润的一半。

后面的proviso (that deductions cannot exceed twice cost ），指的是这样的一种限制：减免不得超过两倍成本，即作为其减免基数的、用来计算减免的（成本+利润）不得超出成本的三倍，这主要是为了防止纳税公司作假。注意句尾的cannot exceed twice cost 不能随便地把它替换成cannot exceed cost twice ，后者的意思变成了不能超过成本的三倍。