单项选择题
第一节
听下面5段对话。每段对话后有一个小题，从题巾所给的[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。 What has happened to steam trains
[A] They have been replaced by electric trains.
B. They have been used for special railway service.
C. They have become more comfortable.