钻孔要素
参考答案：
钻孔具有的结构和尺寸因素。
I recorded the professor’s speech on my cellphone _____ I could listen to it several times later.
A．in case
B．now that
C．even though
D．so that
始建于公元5世纪的布达拉宫，是世界上海拔最高的宫殿建筑群。 ( )
