Rhetorical questions: 不是……吗？ 怎么能……呢？ 哪儿……？
特殊句型 / special sentence patterns
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
A rhetorical question expects no answer: it asserts something forcefully.
- 不是……吗？: "isn't it…?" = it surely is (reminding of a fact): 你不是说没钱了吗？ (Didn't you say you were out of money?)
- 怎么能 / 怎么会……呢？: "how could…?" = no way: 我怎么能不管你呢？ (How could I leave you in the lurch?)
- 哪儿 / 哪里 + V: "where…?" = not at all: 我哪儿有钱啊！ (Me, have money? As if!)
The meaning is always the opposite of the form.
Examples
你不是上个月刚发了工资吗？
Nǐ bú shì shàng ge yuè gāng fā le gōngzī ma?Didn't you just get paid last month?
这么多钱，我怎么能一个人花呢？
Zhème duō qián, wǒ zěnme néng yí ge rén huā ne?How could I spend all this money by myself?
我哪儿知道他的密码啊！
Wǒ nǎr zhīdào tā de mìmǎ a!How would I know his PIN?!
Common mistakes
Mind the intonation: 你不是学生吗？ can be a real question ("Aren't you a student?") or rhetorical ("You're a student, aren't you?!"). Context decides.
✗ 我怎么能去吗？ → ✓ 我怎么能去呢？ (怎么 + 呢, not 吗)