【正确答案】 D

【答案解析】此题属于词语搭配题。读完此句，考生可以发现本句的主要结构是it was not until... that...，这是固定搭配，not until用于强调，例如：It was not until you told me that I knew he was the famous singer．故选[D]until。其余选项:[A]after，[B]by和[C]during都与本题的语意不符。