根据费斯廷格的认知失调理论，消除失调状态的方法不包括（）。

A.改变认知

B.增加认知

C.消除认知

D.改变行为

The fundamental reason why people in general do not speak foreign languages very much better than they do is that they fail to grasp the true nature of the problem of learning to pronounce, and consequently never ______ tackling it in the right way.

A．turn to

B．insist on

C．set about

D．work at