第31题: [填空题]A the nucleus of a cell B cloned human beings C a human being in two years D a law to ban human cloning E a report on human cloning F heavy media coverage The United States will introduce______. 参考答案:D 答案解析:[解析] 文章第2段最后一句提到美国通过了禁止克隆人的法律,故选D。