【题目】The real reason why prices ____ and still are, too high is complex, and no short discussion can satisfactorily explain this problem.
A.were
B.will be
C.have been
D.had been

【答案】A
【解析】句意：过去和现在价格一直居高不下的真正原因很复杂，简短的讨论解释这一问题无法让人满意。根据题干中“and still are”的提示可知过去价格也居高不下，故用一般过去时，表示过去的状态。故选A项。