不是⋯⋯吗
bú shì …… ma
Simple rhetorical questions
不是…吗 isn't a real question — it's a reminder that something was already agreed.
不是 + Statement + 吗 ?
How it works
不是说好了吗？怎么会这样？ — didn't we agree on this? How did it turn out like this? The speaker is objecting, not asking.
English does the same with "didn't you say…?". The structure signals frustration or disbelief.
Examples
bú shì shuō hǎo le ma?
不是说好了吗？
Didn't we agree on this?
nǐ bú shì bù xǐ huan tā ma?
你不是不喜欢他吗？
I thought you didn't like him?
zhè bú shì nǐ de shū ma?
这不是你的书吗？
Isn't this your book?