It was not until dark he found he thought was the correct way to solve the problemA. th

网友回答

(答案→)A. that; what
B. that; that
C. when; what
D. when; that
解析：考查复杂句：第一空是not until 用于强调句，构成it is not until·····that  “直到····才”
第二空后的he thought是插入语，将he thought删掉后会形成这样一个句子：he found      was the correct way to solve the problem.句中的主语和谓语分别是he, found，因此横线上的词要引导一个宾语从句。分析宾语从句的句子成分就会发现，宾语从句的主语缺失，只能用what来充当主语，that在名词性从句中不充当成分。句意：直到天黑他才发现他所想的是解决问题的正确的方法。选A。