当主语 是 the reason 或the cause 时 不能用 because 引导表语从句 所以答案是C.why;that 如果 用 because 应该是 that he was late was _because _he got up late. 主要原因 就是因为 why,because 重复
The reason (why he was late) was that he got up late. 这样很清楚吧?句子成分分析时把次要成分剔除,对分析句子可以简化很多。这里是:(他迟到的)原因是……;而不应该是,原因是因为……。Why he was late?Because he got up late.这样用because