Last year, I usually spent a lot of time ____my  homework. And at the same time, I paid some money ____ my musical classes.

A．to do, for

B．doing, for

C．and do, on

D．with doing, on

特征表理论认为，概念是由（）和概念规则构成的。

A.特异性特征

B.定义性特征

C.概念定义

D.概念例证