But for their assistance, our corporation would not have made such a great progress ______
A、soon than what had expect
B、soon than what was expectedw
C、sooner than what was
D、sooner than what had been expected
【正确答案】：D
【名师解析】:选项D "sooner than what had been expected" 是正确的答案。这个句子是一个虚拟语气的表达，表示如果没有他们的帮助，公司的进步不会像预期的那样快。"Had been expected" 正确地使用了过去完成时态，与句子中的虚拟语气相匹配，表示过去某个时间点之前已经完成的期望。选项A和B中的 "than what had expect" 和 "than what was expected" 语法上不正确，因为它们缺少了连接词 "been"。选项C "sooner than what was" 缺少了动词的过去分词形式，因此也不正确。
