Reconstruct a question, answer pair from this explanation: A girl watching a train speed past is not necessarily waiting for her own to arrive.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Q:Given the sentence "A girl watching a train speed past." is it true that "A girl watches a train speed past while waiting for her own to arrive."?
A:it is not possible to tell