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

问题补充：

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

答案：

(答案→)A. necessarily

B. usually

C. certainly

D. mostly

解析：考查副词辨析。A必要，必然；B通常；C当然，一定；D大部分；not necessarily未必，一定；句意：正如情况所示，便宜的东西未必就质量不好。根据句意说明A正确。