反问句 the rhetorical question
   
    The adverb“难道” is often placed before the subject or the verb of an interrogative sentence to stress the rhetorical tone. It emphasizes the contrary meaning to that of the sentence。“难道说”is also often placed in front of the subject to denote the same meaning, for example,

   都吃完晚饭了，为什么还包饺子？难道还有客人要来吗？（不应该有）
   大家都知道明天要考口语，难道你不知道吗？（应该知道）
   这么点儿小问题，难道我们就解决不了吗？（一定能解决）
   难道说马大为不打算去黄山旅游吗？ （应该去）