who is waiting for you at the school gate?could you tell me 合并句子 急

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who is waiting for you at the school gate?could you tell me 合并句子 急
答案是Could you tell me who is waiting for you at the school gate?为什么是who is?宾语从句的语序不是要陈述语气吗?who is waiting .不是变成问句吗?有人说who 作主语,

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