牛膝具善下行之性，但此特点不用于（）。
A.腰膝酸痛
B.口舌生疮
C.气喘咳嗽
D.难产、胞衣不下
E.阴虚阳亢眩晕
参考答案：C
______ evidence that language acquiring ability must be stimulated.
A．It being
B．It is
C．There is
D．There being
