【题目】The report aims to explain how these conclusions ______.
A. were reached
B. had been reached
C. have reached
D. had reached
在线课程【答案】A
【解析】句义：这篇报告旨在于解释这些结论是如何做出来的。本句实际考察的是固定搭配reach the conclusion得出结论。根据句义可知使用的是被动语态，排除CD项，B项为过去完成时的被动语态，在上下文中没有出现过去的过去的含义。而得出结论是已经发生的事情，故A正确。