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标题: 对"at some time" 的理解 [打印本页]

作者: llmboy 时间: 2009-3-10 09:25
标题: 对"at some time" 的理解

On Wednesday a physician will have exactly one appointment with seven patients- P Q R S T U W- one patient per appointment. The schedule of appointments, chronologically numbered 1 through 7 must meet the following conditions:

（1）Q's appointment is at some time before W's appointment

（2）U's appointment is at some time before P's appointment

（3）Either R or T has appointment 3

（4）S' appointment is either the appointment immediately before or the appointment immediately after R's appointment.

问题 3. If U's appointment is immediately after T's appointment and immediately before R's appointment, then which of one of the following must be true?

(A) Q's appointment is at some time before P's appointment

(B) S's appointment is at some time before P's appointment

(D) W's appointment is immediately before P's appointment

(E) W's appointment is at some time before S's appointment

答案：（B）

我的问题：从答案及条件（2）中包含的“at some time” 来分析，“at some time ”应理解为“任何时候”，而非“某些时候”，否则的话，选（A）也是可以的（Q在某些情况下以在P之前），不知我理解对吗？请赐教，CDers。

[此贴子已经被作者于2009-3-10 16:12:47编辑过]

作者: crusoecrusoe 时间: 2009-3-18 21:40
我的问题：从答案及条件（2）中包含的“at some time” 来分析，“at some time ”应理解为“任何时候”，而非“某些时候”，否则的话，选（A）也是可以的（Q在某些情况下以在P之前），不知我理解对吗？请赐教，CDers。

先不回答你的问题。

问题3给出的条件，推出答案B必然正确。

而答案A，在以下可能下非正确：
T-U-R-S-P-Q-W

题目问的是Must be true，而A选项是可能true，所以不可以选。

关于对于“at some time ”的理解，楼主理解为“任何时候”或“某些时候”，对做题没有影响。（这里的任何时候或某些时候，都是受到限定的）

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