语法与词汇 Unfortunately, it was after two o’clock in the morning _____ he arrived at a solution.
【正确答案】 B
【答案解析】句意：不幸的是，到凌晨2点后他才想到解决办法。本题考查强调句型“It is/was ... that ...”。如强调的主语是人，且为句子的主语时，that可用who来代替。故选B。