体现物质文化的选项是（）。
A、介绍新朋友的时候握手
B、在森林里种树苗
C、饭店里的菜单上列示出了新菜取代旧菜
D、离开某人的公司时说再见
参考答案：B
It was not until the subprime loan crisis (次贷危机) ____ great damage to the American financial
system that Americans ____ the severity of the situation. [ ]
A. caused, realized
B. had caused, realized
C. caused, had realized
D. was causing, had realized
竖井的井壁应是耐火极限不低于( )的非燃烧体。
A．0.5h
B．1h
C．1．5h
D．2h
