-- What were they doing at that time yesterday?
-- They .
A:play soccer
B:played soccer
C:were playing soccer
____
①平面A′FG⊥平面ABC;
②BC∥平面A′DE;
③三棱锥A′﹣DEF的体积最大值为 164 a3;
④动点A′在平面ABC上的射影在线段AF上;
⑤二面角A′﹣DE﹣F大小的范围是0, π2 .
其中正确的命题是____(写出所有正确命题的编号)
我国延续两千多年的封建君主制度和封建剥削土地制度分别终结于 ( )