问题
选择题
为确保信息安全，信息需加密传输，发送方由明文→密文（加密），接收方由密文→明文（解密），已知加密规则为：明文a，b，c，d对应密文a+2b，2b+c，2c+3d，4d．例如，明文1，2，3，4对应密文5，7，18，16．当接收方收到密文14，9，23，28时，则解密得到的明文为（ ）
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答案
答案：B
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为确保信息安全，信息需加密传输，发送方由明文→密文（加密），接收方由密文→明文（解密），已知加密规则为：明文a，b，c，d对应密文a+2b，2b+c，2c+3d，4d．例如，明文1，2，3，4对应密文5，7，18，16．当接收方收到密文14，9，23，28时，则解密得到的明文为（ ）
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答案：B
| Nine states and the District of Columbia are doing away with the sales tax on items such as clothes, shoes and even notebooks over the next few weeks, just in time for back-to- school shopping. Most of the promotions last only a few days, so shoppers will have to act quickly to get a tax break. The tax holidays, which have already expired in two other states, apply to small and large items. For example, the tax break applies to any school supply that costs $15 or less in New Mexico. In Massachusetts, it covers most retail purchases of $2,500 or less. Stores may offer additional savings because these events "give retailers an opportunity to have a sale on top of what the state is doing," says Verenda Smith, government affairs associate at the Federation of Tax Administrators. No industry-wide figures are available about how much consumers save annually from these tax breaks. But Texas estimates that shoppers will save $47.4 million in taxes this year, nearly a 3 percent increase from the previous year. Massachusetts says shoppers saved roughly $10 million in taxes during its 2005 event. States that cast aside these promotions when a slow economy pinched state budgets are now reviving them in hopes of stimulating local economies. Some states also believe the gain in consumer goodwill helps balance out the loss in tax revenue. In some cases, tax losses are minimal because serious shoppers don’t stop at clothes and books. "While states give up sales tax, they usually break even on sales-tax collection," says J. Craig Shearman, a vice-president at the National Retail Federation. Sophie Beckmann, a certified public accountant at A. G. Edwards in St. Louis, says she’ll avoid that temptation by making a list of necessities. On the Missouri resident’s shopping list: notebooks, pencils, glue and three or four outfits for her son, who is entering the fifth grade this month. She plans to pocket any tax savings. "When you start buying more and spending more just because of the savings, then you’re not doing yourself a favor," Beckmann says. |
When he says in Paragraph 5, "While states give up sales tax, they usually break even on sales-tax collection", J. Craig Shearman actually means that ______ .
A．a vice-president at the National Retail Federation can say whatever he or she likes
B．only when a state gives up sales tax can it achieve break even in collection of taxes
C．tax losses are nothing for a state since serious shoppers buy more than just clothes or shoes
D．when people come to buy sales-tax-free items, they will buy other things that are still taxed