以补开塞为（）。
A.反治
B.正治
C.标本兼治
D.扶正祛邪
E.扶正固表
参考答案：A
--- Look at ______ book on the desk . Is it ______ useful one ?
--Yes, it is . In the book there is much advice on how to learn math well.
A．a, the
B．the, a
C．the, an
D．a, an
多模光纤的标准工作波长包括以下哪些？
