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. what did the speakers plan to do at first?
a. go shopping. b. play a game. c. watch a movie.
2. what are the speakers mainly talking about?
a. water. b. the environment. c. human health.
