As is often the case, the fact that something is cheap doesn’t _____ mean it’s of low quality.

A．necessarily

B．usually

C．certainly

D．mostly

经后发热，形寒，自汗，神疲乏力，气短懒言，脉细弱，首选方是（）

A.清经散

B.两地汤

C.补中益气汤

D.血府逐瘀汤

E.知柏地黄汤