听下面5段对话或独白。每段对话或独白后有几个小题，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。听每段对话或独白前，你将有5秒钟的时间阅读各个小题；听完后，各小题将给出5秒钟的作答时间。每段对话或独白读两遍。 How many hours did Mr. Brown’s flight last

A．see
B．hear
C．know
D．understand

A． Because his wife told him to.
B． Because he feels tired.
C． Because his wife feels tired.