After＿＿＿seemed a hopeless wait, four coal-miners trapped in the mine for 125 hours were finally rescued in Heilongjiang Province．
A. when
B. that
C. it
D. what
网友回答
A. when
B. that
C. it
(答案→)D. what
解析：经过一段无望的等待之后，被困矿工终于得救。what引导名词从句并在从句中作主语，what从句做介词after的宾语。A项when在名词从句中做时间状语，排除。B项引导名词从句不在从句中作成分。C项不引导从句。故D项正确。