题目

某探险者在野外攀岩时，踩落一小石块，约5s后听到石头直接落到崖底的声音，探险者离崖底的高度最接近的是（） A . 25m B . 50m C . 110m D . 150m 答案：C It was not until dark ______ he found ______ he thought was the correct way to solve the problem. A. that; what       B. that; that          C. when; what     D. when; that