Once you can say 我在吃饭 ("I'm eating") with the progressive marker 在/正在, two questions immediately follow: how do you say "I'm not eating," and how do you say "I was eating"? English answers both by changing the verb "be" — am not, was — but Chinese has no "be" to change here. Instead, you negate the progressive with 没在 and you build the past by adding a time phrase while leaving 在 completely untouched. The key idea to absorb up front: 在 carries no tense at all. It marks "in progress," and whether that progress is happening now or was happening yesterday is decided entirely by the time words around it.
Negating: 没在 and 不是在
To say an action is not going on, put 没(有)在 in front of the verb — not 不在. The reason is the core logic of 没 vs 不: 没 denies that an event has occurred or is occurring, while 不 denies willingness, habit, or a general truth. An action-in-progress is a concrete, ongoing occurrence, so its non-occurrence is 没 territory. A bare 不在 doesn't mean "not V-ing" — 不在 on its own means "not present / not here," which is why *我不在睡觉 sounds broken.
别叫我，我没在睡觉，只是闭着眼睛休息。
bié jiào wǒ, wǒ méi zài shuìjiào, zhǐshì bì zhe yǎnjing xiūxi
Don't call out to me — I'm not sleeping, I've just got my eyes shut, resting. (informal)
我没在玩手机，我在查餐厅的地址。
wǒ méi zài wán shǒujī, wǒ zài chá cāntīng de dìzhǐ
I'm not messing around on my phone — I'm looking up the restaurant's address. (informal)
A second, subtly different negation is 不是在 — literally "it is not (the case) that … V-ing." This doesn't deny the action so much as reject a framing or an assumption the listener has made. It pairs beautifully with a correction:
我是认真的，我不是在开玩笑。
wǒ shì rènzhēn de, wǒ bú shì zài kāi wánxiào
I mean it — I'm not joking. (neutral)
你误会了，我不是在批评你，我只是想帮你。
nǐ wùhuì le, wǒ bú shì zài pīpíng nǐ, wǒ zhǐshì xiǎng bāng nǐ
You've misunderstood — I'm not criticizing you, I just want to help. (neutral)
Past-framing: add a time phrase, keep 在
To say "I was V-ing," you do not hunt for a past-tense form — there isn't one. You take the ordinary progressive 在/正在 + V and place a past time phrase beside it. The time phrase does all the work of locating the event in the past; 在 just keeps signalling "in progress at that time."
昨天你打电话的时候，我正在开车，所以没接。
zuótiān nǐ dǎ diànhuà de shíhou, wǒ zhèngzài kāichē, suǒyǐ méi jiē
When you called yesterday I was driving, so I didn't pick up. (neutral)
那时候我们正在吃晚饭，突然停电了。
nà shíhou wǒmen zhèngzài chī wǎnfàn, tūrán tíngdiàn le
We were right in the middle of dinner when the power suddenly went out. (informal)
我进门的时候，妈妈在厨房做饭，一点都没听见。
wǒ jìn mén de shíhou, māma zài chúfáng zuò fàn, yìdiǎn dōu méi tīngjiàn
When I came in, Mom was cooking in the kitchen and didn't hear a thing. (informal)
Notice the recurring shape: a when-clause (…的时候, 那时候, 昨天下午) sets the past moment, and the 在-clause describes what was ongoing at that moment. This is exactly how English "when… I was …" works — except English also inflects "be" to was, whereas Chinese leaves 在 identical to its present-tense self. You can even negate inside a past frame: 没在 slots in just the same.
昨天开会的时候我没在听，走神了，所以没听到老板说什么。
zuótiān kāihuì de shíhou wǒ méi zài tīng, zǒushén le, suǒyǐ méi tīngdào lǎobǎn shuō shénme
During yesterday's meeting I wasn't listening — I zoned out, so I didn't catch what the boss said. (informal)
Here is the whole system on one page:
| Function | Structure | Example |
|---|---|---|
| Progressive (now) | 在／正在 + V | 我在吃饭 — I'm eating |
| Negated progressive | 没(有)在 + V | 我没在吃饭 — I'm not eating |
| Deny the framing | 不是在 + V | 我不是在吃饭 — it's not that I'm eating |
| Past progressive | time phrase + 在／正在 + V | 那时候我在吃饭 — I was eating then |
| Negated past progressive | time phrase + 没在 + V | 那时候我没在吃饭 — I wasn't eating then |
Common Mistakes
1. Negating with 不在 instead of 没在. 不在 means "not present," so it can't express "not doing something right now."
❌ 你敲门的时候我不在睡觉。
Wrong for 'I wasn't sleeping' — 不在 reads as 'wasn't there'; an ongoing action is negated with 没在.
✅ 你敲门的时候我没在睡觉。
nǐ qiāo mén de shíhou wǒ méi zài shuìjiào
I wasn't sleeping when you knocked. — 没在 negates the ongoing action.
2. Putting the negator after 在. The negation always precedes 在, never follows it.
❌ 我在没看电视，我在写作业。
Wrong word order — the negator can't sit after 在.
✅ 我没在看电视，我在写作业。
wǒ méi zài kàn diànshì, wǒ zài xiě zuòyè
I'm not watching TV, I'm doing my homework. — 没 goes before 在.
3. Adding 了 to make the progressive "past." 了 signals completion or change of state; bolting it onto 在 + V doesn't create a past progressive, it just breaks the sentence.
❌ 昨天下午我在学习了。
Wrong — a past progressive doesn't take 了; use a time phrase with plain 在.
✅ 昨天下午我在学习。
zuótiān xiàwǔ wǒ zài xuéxí
I was studying yesterday afternoon. — the time phrase alone marks the past.
4. Using 了 instead of 在 for "was V-ing." A bare V + 了 gives a completed reading ("I drove / I finished driving"), not the ongoing "was driving" you want.
❌ 你打电话的时候，我开车了。
Wrong for 'I was driving' — V + 了 reads as a completed action ('I drove'), not an action in progress.
✅ 你打电话的时候，我在开车。
nǐ dǎ diànhuà de shíhou, wǒ zài kāichē
I was driving when you called. — 在 keeps the action ongoing.
Key Takeaways
- Negate a progressive with 没(有)在 + V ("not doing it"), never 不在 (which means "not present").
- Use 不是在 + V to reject a framing — "it's not that I'm V-ing" — rather than the activity itself.
- There is no past-progressive form: keep 在／正在 exactly as is and add a past time phrase (昨天, 那时候, …的时候) to mean "was V-ing."
- 在 is tenseless — the same marker serves present and past; only the time word moves.
- Never add 了 to a progressive to "make it past" — 了 marks completion and clashes with ongoing 在.
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- Progressive 在 / 正在 / 正 (+ V): In the Middle OfHSK 1 — 在 before a verb marks an action in progress — 我在吃饭 'I'm eating'. 正在 stresses 'right in the middle of it now', bare 正 pins the coinciding moment. It's aspect, not tense, so it works in the past and future too.
- 没(有) (méi yǒu): Negating 有 and Completed ActionHSK 1 — 没(有) does two jobs: it is the only way to negate 有 (有 is never 不有), and it negates completed or experienced actions — 我没吃 'I didn't eat', dropping the 了. Think of 没 as the completion/existence/change negator.
- How to Talk About the Past Without TenseHSK 2 — With no past tense, Chinese conveys 'past' through time words (昨天), 了 for completion and 过 for experience — but many past sentences, especially states and habits, take no marker at all.
- Two Negators: 不 (bù) vs 没 (méi)HSK 1 — Mandarin has exactly two everyday negators. 不 (bù) negates the habitual, willed, future, and all adjectives and modal verbs; 没(有) (méi yǒu) negates the verb 有 and any completed or experienced action. The split is NOT about tense — it's habit/intention/quality (不) vs completion/existence (没).