A. Oh, I'm sorry.
B. It's green. We can go.
C. They're waiting.
D. I'm going to work.
E. Thank you.
使平面α∥平面β的一个条件是( )
如图,在正方形ABCD中,E是BC的中点,△DEF的面积等于2,则此正方形ABCD的面积等于( )