—So he does.
A:some good pieces of news
B:some pieces of good news
C:some good piece of news
D:some piece of good news
如图,AD是△ABC的角平分线,DF⊥AB,垂足为F,DE=DG,△ADG和△AED的面积分别为50和38,则△EDF的面积为( )
如果a是有理数,下列各式一定为正数的( )