【请教NN】白勇语法全解 P157第18题

sophialaw81

P157-18
The voluminous personal papers of Thomas Alava Edison reveal that his inventions typically did not spring to life in a flash of inspiration but evolved slowly from previous works.
C) did not spring to life in a flash of inspiration but evolved slowly
D)  did not spring to life in a flash of inspiration but had slowly evolved
解释说选C，但我还是觉得D模棱两可：previous 不是时间提示词吗？不是提示inventions在works后产生的吗？那evolve 为什么不用had evolved呢? 想不明白呢
请大家帮忙解答，非常感谢~~~~~

零度变蓝

but 表示并列，前后时态一致