第一节
听力理解第一节 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。
Who was introduced

A．easy
B．difficult
C．hard
D．common

A． Since last night.
B． For a week.
C． Since last week.