单选题
Unfortunately, any benefits gained by lowering prices never ______ if they are achieved by a reduction in quality.
【正确答案】
A
【答案解析】句中没有谓语动词，if they are achieved by a reduction in quality是条件状语从句，因此全句无宾语，横线处应填入不及物动词。(D)retain(保留)是及物动词。(B)pass(经过，通过)虽然是不及物动词，但是要后接表示场所的状语。(C)spend(消耗，花费)与句意不符。故选择(A)last(持久)。