xy"-y’=x2的通解为______．
参考答案：
解析：[详解]
在抗感染免疫的早期起重要免疫作用的抗体是（）
A.IgG
B.IgM
C.IgA
D.IgD
E.IgE
Her daughter enjoys _____ the piano very much.[ ]
A. play
B. to play
C. playing
D. played
