扩句
①老师是学生。
②我们走。
①我们的老师是一个从城里来的女学生。②我们沿着小路走。
(Ⅰ)求 CDAB 的值;
(Ⅱ)若AF= 12 FC,求证:BD+DC=2AB.
Mary keeps talking about the party. She had a very good time,_______?