标题: 关于时态的困惑 [打印本页] 作者: 哲思雅 时间: 2010-10-9 10:32 标题: 关于时态的困惑 XDF 蓝皮书Sec one 3. Although the Supreme Court ruled as long age as 1880 that Blacks could not be excluded outright from jury service, nearly a century of case-by-case adjudication has been necessary to develop and enforce the principle that all juries must be drawn from "a fair cross section of the community." (A) has been necessary to develop and enforce the principle that all juries must be (B)was necessary for developing and enforcing the principle of all juries being (C)was to be necessary in developing and enforcing the principle of all juries to be (D)is necessary to develop and enforce the principle that all juries must be (E)will be necessary for developing and enforcing the principle of all juries being 我的问题是：为什么时态用的是has been 呢？从题中哪里能得出应该使用完成时态？不解 作者: wkz502 时间: 2010-10-9 10:51
原文的意思大概是：虽然最高法院在1880年就规定了黑人不能被陪审团所排除，不过还是用了将近一世纪，经历了一个案子接一个案子的裁决，才慢慢发展并执行这条准则。