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

(C)  S's appointment  is immediately before Q'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。