单选题 It was not until I ______ your letter that I ______ all about the matter.
【正确答案】 D
【答案解析】[考点] 时态 [解析] Not until用否定句，“直到……，直到……才”，例：It was not until he told me that I knew it.因为是过去时，所以条件句应比过去时更向后推，用过去完成时。