第一部分：听力（共两节，满分30分）
第一节（共5小题；每小题1.5分，满分7.5分）
听下面5段对话。每段对话后有一个小题,从题中所给的A、B、C三个选项中选出最佳选项，并标在试卷的相应位置。听完每段对话后，你都有10秒钟的时间来回答有关小题和阅读下一小题。每段对话仅读一遍。
1. Where are they talking?
A. In a house. B. In a park C. In a library.
2. What can we learn from this conversation?
A. This lab is generally locked on Saturdays.
B. Something strange happened in the lab on Saturday.
C. The lab should never be locked.
