不 for habit/future, 没(有) for a past event
不 (bù) negates habitual actions, future plans and willingness/ability: 我不吃辣的。(Wǒ bù chī là de.) — I do not eat spicy food (habit). 我明天不去学校。— I will not go tomorrow (future). 没(有) negates a specific completed or past action: 我昨天没(有)去学校。(Wǒ zuótiān méi(yǒu) qù xuéxiào.) — I did not go to school yesterday. The test: is the sentence a habit/future plan (不) or a specific past event (没有)?
有 is always negated with 没; drop 了 after 没
Two fixed rules outside the general time-frame test. First, 有 (yǒu, to have) is negated only by 没, in every tense: 我没有钱。(Wǒ méiyǒu qián.) — I have no money. Never 我不有钱 -- that form does not exist. Second, when 没(有) negates a completed action, the 了 is dropped: 我昨天去了学校 (I went to school) becomes 我昨天没(有)去学校 (I did not go) — NOT 我昨天没(有)去了学校. 了 and 没(有) never co-occur on the same verb.
是……的 emphasises when/where/how/who
是……的 does not state THAT an event happened (了 does that); it highlights a known DETAIL — the time, place, manner or agent. Pattern: Subject + (是) + detail phrase + Verb (+ Object) + 的. 你是什么时候来的？(Nǐ shì shénme shíhou lái de?) — When did you come? 我是坐飞机来的。(Wǒ shì zuò fēijī lái de.) — I came BY PLANE. 他是在伦敦出生的。— He was born IN LONDON. The final 的 is required; 了 is not used alongside it.
Drawn from real examiner reports.
Using 不 for a specific past event
A specific completed or past event takes 没(有), not 不. ✗ 昨天我不来学校，因为我生病了。(不 wrongly used for a one-off past event) ✓ 昨天我没(有)来学校，因为我生病了。(Zuótiān wǒ méi(yǒu) lái xuéxiào, yīnwèi wǒ shēngbìng le.) — I did not come to school yesterday, because I was ill. Ask: is this ONE specific past event? Then use 没(有).
Missing or misreading a negative word flips the answer in Listening (s22 P11 Q17, Q19), and getting the past/future time frame wrong is the single most common Speaking-grammar error (s22, s23).
Keeping 了 after 没(有)
When 没(有) negates a completed action, drop 了 entirely -- the two never share a verb. ✗ 我昨天没去了图书馆。(了 must not appear with 没) ✓ 昨天我没去图书馆，因为下雨。(Zuótiān wǒ méi qù túshūguǎn, yīnwèi xiàyǔ.) — I did not go to the library yesterday. The time word 昨天 also moves before the verb, not after the object.
The most heavily documented grammar error across both sittings is 了 aspect-marker misuse -- missing, misplaced or used where it does not belong (s23 P41; s22).
Mixing 了 into a 是……的 sentence
Once 是 introduces the emphasised detail, 了 is replaced by the sentence-final 的, never combined with it. ✗ 我是昨天去了北京。(是 mixed with 了) ✓ 我是昨天去北京的。(Wǒ shì zuótiān qù Běijīng de.) — I went to Beijing yesterday (emphasising WHEN). The 的 carries the structure; adding 了 as well is redundant and wrong.
A documented instance of the most-cited grammar error, 了 misuse where it does not belong (s22, s23).
Negating 有 with 不 instead of 没
有 (to have) is negated ONLY by 没, in every tense -- 不有 simply does not exist as a form. ✗ 我不有钱。 ✓ 我没有钱。(Wǒ méiyǒu qián.) — I do not have money. This holds regardless of time frame: past, present or future possession is always negated with 没有, never 不有. Even when the rest of the sentence is about the future, 有 keeps 没.
Using 没 for a habitual statement
A habitual statement takes 不, not 没 -- and the frequency adverb sits before the verb, not stranded at the end. ✗ 我没吃早饭每天。(没 clashes with the habit; 每天 misplaced) ✓ 我每天不吃早饭。(Wǒ měitiān bù chī zǎofàn.) — I do not eat breakfast every day. 没 is for a specific completed event, not a recurring routine.
Dropping the final 的 in 是……的
The 是……的 structure must end in 的 -- omitting it breaks the emphasis and the sentence. ✗ 你是什么时候来？(final 的 missing) ✓ 你是什么时候来的？(Nǐ shì shénme shíhou lái de?) — When did you come? 是 can be dropped in casual speech (你什么时候来的？), but the closing 的 can never be dropped -- it is the one obligatory part of the pattern.
了 is not a past tense you can just negate
了 marks completion or a change of state, not "past tense" as a grammatical category, and 不 cannot simply be bolted onto a 了-sentence. ✗ 我不去了学校。(不 + 了 on the same verb is ungrammatical) ✓ 我没去学校。(Wǒ méi qù xuéxiào.) — I did not go to school. To negate a completed action, replace 了 with 没(有) in front of the verb -- 了 is removed, not kept alongside 不 or 没.
是……的 is not optional decoration
是……的 is not decorative -- it flags that the FACT of the event is already known and the new information is the time/place/manner/agent detail. Compare: 他去了北京。(Tā qùle Běijīng.) — He went to Beijing (new: the trip happened) versus 他是坐火车去北京的。(Tā shì zuò huǒchē qù Běijīng de.) — He went BY TRAIN (trip known; new: the transport). Swapping one for the other changes the meaning.
Ask if it is 有 first
Before negating, check whether the verb is 有 (possession). If it is, always use 没 (我没有……), whatever the tense -- 不有 never exists. This one check removes the most basic negation error before you even weigh time frame.
Habit/future → 不; past event → 没(有)
If the verb is not 有, decide the time frame: a habit, future plan or willingness takes 不; one specific completed or past event takes 没(有), with any 了 on that verb dropped. 我不吃辣的 (habit) versus 我昨天没去 (past event).
Switch to 是……的 to highlight a detail
If the task asks you to highlight WHEN, WHERE, HOW or WHO for an event the reader already knows happened, use 是……的: put the detail straight after (是), keep the verb, and end in 的 -- do not add 了. 我是坐飞机来的。
This grammar point (Section G, G4) covers two closely-linked structures: choosing between 不 (bù) and 没(有) (méi(yǒu)) to negate a sentence, and using 是……的 (shì…de) to emphasise the time, place, manner or agent of an event already known to have happened. Both appear across Reading, Listening, Writing and Speaking whenever a task involves talking about what did or did not happen.
不 (bù) negates a habitual action, a future plan, or willingness/ability -- it does NOT refer to one specific completed event. 没(有) (méi(yǒu)) negates a specific completed action, something that did or did not happen in the past, and is the ONLY word that ever negates 有 (yǒu — to have/possess), in any tense. 是……的 (shì…de) is used only when the LISTENER already knows an event happened, and the speaker wants to highlight a detail about it -- when, where, how, or by whom.
Say in Chinese: I did not go to school yesterday. (completed past event, use 没(有))
写出三个用「不」表示习惯性或将来动作否定的例句，和三个用「没(有)」表示已完成动作否定的例句，并标注拼音。
Level-of-response questions with model answers and mark scheme rubrics.
请给你的朋友写一条短信，说说你上个周末做了什么、没做什么。短信里要写清楚以下几点，并正确使用「不」和「没(有)」：（1）一件你上个周末已经做的事；（2）一件你上个周末没有做的事（用「没(有)」）；（3）一件你平时不做/不喜欢做的事（用「不」，表示习惯）。请用中文（汉字）书写，约80-90字，注意短信的语气比较随意。（8分）
你上个月去了一个地方旅行，你的同学都已经知道你去旅行这件事了。请用「是……的」句型，给同学写一段介绍，说明以下细节：（1）你是什么时候去的；（2）你是跟谁一起去的；（3）你是怎么去的（交通方式）。请用中文（汉字）书写，约80-90字，全文正确使用「是……的」结构，句末不要遗漏「的」，也不要再加「了」。（8分）
