在本节中,你将听到15个对话,每个对话有一个问题。请从[A]、[B]、[c]三个选项中选出答案,并标在试卷的相应位置。每段对话后有15秒钟的停顿,以便回答问题并阅读下一问题及其选项。每段对话读两遍。下面,请听这些对话。 When did it begin to rain
At 6 o’ clock.
Before I got home.
C. When I got home.
当Intel 8251A工作在同步方式时,引脚同步检测SYNDET可作为输入或输出信号使用。若工作在外同步方式,该引脚为______;若工作在内同步方式,该引脚为______。
"Take pan of the Science Center home with you" means that______.
A. [A] visitors can buy something there and take them home
B. the Science Center may be sold to visitors
C. the visitors can make the Science Center their home