因式分
(1)25a-5a2;
(2)(x-y)2+4xy.
(1)25a-5a2=5a(5-a);
(2)(x-y)2+4xy,
=x2+2xy+y2,
=(x+y)2.
—_____ they are talking to each other!
—Yes. They are really happy to see each other. [ ]
A. What excited
B. How excited
C. What excitedly
D. How excitedly
压实机械分为( )等几种基本类型。
A.静压碾压
B.羊脚碾
C.振动碾压
D.气胎碾
E.夯击