Rhetorical questions with 难道…吗 — Chinese grammar (HSK 4)

难道 + Statement + 吗？

难道 (nándào) turns a question into a rhetorical challenge, like English "Surely you don't mean ...?" or "Don't tell me ...". The speaker already knows the answer, and the real meaning is the opposite of the question: 难道你不知道吗？ means "You must know!". It sits after the subject or at the very start, with 吗 at the end.

Examples

难道你不知道今天有考试吗？ Nándào nǐ bù zhīdào jīntiān yǒu kǎoshì ma?	Don't tell me you didn't know there is an exam today?
你难道忘记了我们的约会吗？ Nǐ nándào wàngjì le wǒmen de yuēhuì ma?	Surely you haven't forgotten our date?
这个问题很简单，难道还要问老师吗？ Zhè ge wèntí hěn jiǎndān, nándào hái yào wèn lǎoshī ma?	This question is easy; do you really need to ask the teacher?

Tip: Do not answer a 难道 question with 是 / 不是; it is not a real question but a reproach.