It was not until dark he found he thought was the correct way to solve the problem．
A. when; that
B. that; that
C. when; what
D. that; what
网友回答
A. when; that
B. that; that
C. when; what
(答案→)D. that; what
解析：考查复杂句：第一空填that， It it not until...that... 是强调句“直到...才”，第二空填what，引导主语从句：what he thought “他所想的” 句意：直到天黑，他才发觉他刚才所想的解决问题的方法是正确的。选D。