A study published in the Journal of the American Medical Association in 2003 reported that dark chocolate may lower your blood pressure. Researchers at the University of Cologne studied men and women who were recently diagnosed with mild high blood pressure. Half were given 100g (fabout 3.5 ounces) of dark chocolate per day and half were given white chocolate. After only two weeks systolic (收缩的) blood pressure decreased on average by five points and diastolic (以及舒张的) blood pressure by two points in those consuming dark chocolate, but not those consuming white chocolate. In a similar study, researchers from Italy reported in the American Heart Association journal Hypertension that 3.5 ounces of dark chocolate for one week lowered systolic blood pressure by 12 points and diastolic blood pressure by 8.5 points when blood pressure was monitored continuously for 24 hours. Insulin (胰岛素) sensitivity and LDL cholesterol also improved. No benefits were seen with white chocolate. Another study published in the Journal of the American College of Cardiology found that chocolate may help repair damage to smokers' blood vessels, at least temporarily. why? Chocolate increases your body' s production of nitric oxide (一氧化氮), a powerful substance that causes your blood vessels to relax and dilate. This, in turn, causes an increase in blood flow and a decrease in blood pressure--like opening a water spigot (水龙头). A study published in July in the Journal of the American Medical Association reported that just 30 calories per day of dark chocolate lowered blood pressure and increased nitric oxide production after 18 weeks. Nitric oxide is also stimulated by drugs such as Viagra and Levitra, which increase blood flow to the penis and enhance erections. This may be one of the reasons why chocolate has had a long reputation as an aphrodisiac (壮阳药). Casanova (卡萨诺瓦) is said to have considered it as his "favorite breakfast dish. " Chocolate also contains phenylethylamine (苯乙胺), which research suggests is a stimulant that is released when you' re interacting with someone intimately.
单选题
Which of the following statements is true about the subjects in the 2003 study?
单选题
What is nitric oxide according to the passage?
【正确答案】
B
【答案解析】根据题干定位到第三段第二句：Chocolate increases your body's production of nitric oxide (一氧化氮), a powerful substanct that causes your blood vessels to relax and dilate(巧克力提高了体内一氧化氮的产生，一氧化氮是引起血管舒张和收缩的一种效力非常强的物质)。四个选项中B选项最切合原文，因此为本题的正确答案。
单选题
According to a study published in July, 30 calories of dark chocolate lowered blood pressure and increased production of nitric oxide
【正确答案】
D
【答案解析】根据题干定位到第三段最后一句：A study published in July in the Journal of the American Medical Association reported that just 30 calories per day of dark chocolate lowered blood pressure and increased nitric oxide production after 18 weeks(七月份在美国医学联合会杂志上发表的一项研究显示，每天30卡路里的黑巧克力会在18周后降低血压并且增加一氧化氮的生成)。显然本题的正确答案为D。
单选题
Chocolate has long been considered as an aphrodisiac because
【正确答案】
A
【答案解析】根据题干定位到最后一段第一、二句：Nitric oxide is also stimulated by drugs such as Viagra and Levitra, which increase blood flow to the penis and enhance erections. This may be one of the reasons why chocolate has had a long reputation as an aphrodisiac(一氧化氮也会被伟哥和乐维它之类的药物所激发，这会增加阴茎的血流量，提高勃起，这可能是巧克力一直被认为是一种壮阳药的原因之一)。由此不难推断，巧克力之所以被认为有壮阳的效果，是因为它和伟哥等药物有着相同的功能：提高一氧化氮的产生。因此本题的正确答案为A。