再问 og-172

我笨，我努力

请教OG172
172. There is a great deal of geographical variation in the frequency of many surgical
procedures—up to tenfold variation per hundred thousand between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies.
To support a conclusion that much of the variation is due to unnecessary surgical
procedures, it would be most important to establish which of the following?
(A) A local board of review at each hospital examines the records of every operation to determine whether the surgical procedure was necessary.
(B) The variation is unrelated to factors (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered.
(C) There are several categories of surgical procedure (other than hysterectomies, prostatectomies, and tonsillectomies) that are often performed unnecessarily.
(D) For certain surgical procedures, it is difficult to determine after the operation whether the procedures were necessary or whether alternative treatment would have succeeded.
(E) With respect to how often they are performed unnecessarily, hysterectomies,
prostatectomies, and tonsillectomies are representative of surgical procedures in general.
我的问题是有几个关系没有搞清楚：

1.surgical procedures 中存在 geographical variation 。geographical 与surgical 存在什么关系？

是 geographical 引起geographical的吗？但从文中我得不到那样的关系？

2.unnecessary surgical procedures 与geographical  viariation 有什么关系？

3.necessary 与 unnecessary 之间的界限是怎么界定得？

请多多指教。

顺便多问一下，我逻辑的正确率还可以，但是时间比较慢，平均三分钟左右，我该怎样提高自己比较好？有什么好的训练方法吗？谢谢

海水无情

顺便多问一下，我逻辑的正确率还可以，但是时间比较慢，平均三分钟左右，我该怎样提高自己比较好？有什么好的训练方法吗？谢谢

每次作题目都有秒表扣时间. 必须2分以内.

不然不如不做.

我笨，我努力

再顶一下请求指点

ReedSong

说一下我的理解：

1、geographical 与surgical 存在什么关系？

文中说：对于H/P/T三种病，不同地区在是否实施手术方面的比例差距很大，up to tenfold variation per hundred thousand between different areas：举例来说，A地区每一万例的病中，100例实施了手术，但在B地区，每一万例的病中，却多达1000实施了手术。所以文章得出结论：这种地区之间实施手术比例的变化是因为做了有很多不必要做的手术。（例如：认为B地区中的900例手术是其实没必要做的，但实际却做了。）

2.unnecessary surgical procedures 与geographical  variation 有什么关系？

文中的结论认为：unnecessary surgical procedures的存在是存在geographical  variation的原因。

3.necessary 与 unnecessary 之间的界限是怎么界定得？

文中并没有提到两者的界定问题。

答案B排除它因，从而对结论进行了加强。

另外关于做题时间的问题，我同意海水的看法，我也经历过这样一个转变过程，不保证做题速度的正确率，在实战中会比较吃亏。主要是一个习惯的养成，掐表逼迫自己加快速度，习惯了就好了。

我笨，我努力

Thank you very much！多谢两位的指点！

KATIEUS