Logically, 差点没 is not that different from 差点. In fact, you shouldn't think of it as a single word; think of the 没 as belonging to what follows 差点 and it makes more sense. Still, it can be a little confusing, and is worth a closer look.
Logical Structure
Subj. + 差点 + 没 + Verb Phrase
Note that the "Verb Phrase" part is a desired result. So this structure is literally saying, "almost didn't [Verb Phrase]."
Also note that because you're using 没, you don't use 了 after the verb phrase.
Examples
- 我 差点儿 没 想 起来。I did remember it. Wǒ chàdiǎnr méi xiǎng qǐlái.I almost forgot it.
- 我 差点 没 赶 上 火车。 I almost missed it, but I didn't.Wǒ chàdiǎn méi gǎnshàng huǒchē.I didn't miss the train.
- 他 差点 没 通过 考试。He did pass it.Tā chàdiǎn méi tōngguò kǎoshì.He barely passed the examination.
- 排队 的 人 太 多 了，差点儿 没 买到。I did get it.Páiduì de rén tài duō le, chàdiǎnr méi mǎidào.The waiting line is too long. I almost didn't get it.
See also
Sources and further reading
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Category:B2 grammar points