A:b(a+b)(a−b)
B:b(a−b)2
C:b(a2−b2)
D:b(a+b)2
下列各组生物中,二者都属于病原体的一组是( )
____ (not finish) the homework, the little girl doesn't dare to go to school.
2=____=____=____=____=____=____=____=____=____。