過（經驗）

1. Experiential Aspect & Discontinuity Effect
The verbal suffix 過 (gwo3) indicates that an action happened as a past lifetime experience ('have ever done' or 'have done before'). Unlike the perfective marker 咗 (zo2), which often implies a persisting result, 過 carries a discontinuity effect—the past situation is over and no longer holds true right now.

Comparing 咗 (zo2) vs 過 (gwo3):
• 佢去咗日本 (keoi5 heoi3 zo2 jat6 bun2) = He went / has gone to Japan (he is currently away or still there).
• 佢去過日本 (keoi5 heoi3 gwo3 jat6 bun2) = He has been to Japan before (he has since returned).
• 佢斷過骨 (keoi5 dyun6 gwo3 gwat1) = He has broken a bone before (it is healed now).

With Adjectives:
Because of this discontinuity effect, 過 can also attach to adjectives to mean 'used to be [adjective] but isn't anymore':
• 佢以前肥過 (keoi5 ji5 cin4 fei4 gwo3) = He used to be fat (but he is not anymore).

2. Retaining 過 Under Negation
To express 'have not / have never done before', use 冇 (mou5) or 未 (mei6) before the verb. Unlike 咗 (zo2) which drops under negation (e.g., 冇食, not *冇食咗), 過 must be retained. Note the semantic difference between the two negators:
• 冇 + V + 過 is a factual negation of experience ('have not done before'): 我冇食過呢啲嘢 (ngo5 mou5 sik6 gwo3 nei1 di1 je5) = I haven't eaten this before.
• 未 + V + 過 implies an expectation of doing it in the future ('have not done before yet'): 我未聽過呢首歌 (ngo5 mei6 teng1 gwo3 nei1 sau2 go1) = I have never heard this song before (but I might now).

3. Asking Experiential Questions & Short Answers
There are two common ways to ask if someone has ever done something:
• Neutral question: Use 有冇 (jau5 mou5) before the verb. This is the primary way to ask 'have you ever...?':
你有冇去過日本呀？ (nei5 jau5 mou5 heoi3 gwo3 jat6 bun2 aa3?) = Have you ever been to Japan?
• Expectation question: Use V + 過 + (Object) + 未? This carries the specific nuance of 'have you done X yet?':
你食過蛇膽未？ (nei5 sik6 gwo3 se4 daam2 mei6?) = Have you eaten snake gallbladder yet?

Short Answers:
For 有冇 questions:
• Yes: 有 (jau5) / 有呀 (jau5 aa3), or [Verb] + 過 (e.g., 去過 heoi3 gwo3)
• No: 冇 (mou5) / 冇呀 (mou5 aa3), or 冇 + [Verb] + 過 (e.g., 冇去過 mou5 heoi3 gwo3)
• Not yet: 未 (mei6) / 未呀 (mei6 aa3)

For V + 過 + 未 questions:
• Yes: [Verb] + 過 (gwo3) (e.g., 食過 sik6 gwo3)
• Not yet: 未 (mei6) / 未呀 (mei6 aa3)

4. Stating Frequency
To state how many times you have done something, use the pattern V + 過 + (Object) + Number + 次 (ci3):
• 我去過日本兩次 (ngo5 heoi3 gwo3 jat6 bun2 loeng5 ci3) = I have been to Japan twice.
• 佢食過一次 (keoi5 sik6 gwo3 jat1 ci3) = He has eaten it once.

5. Verb-Object (VO) Compounds
When using separable compound verbs, 過 attaches directly to the verb root before the object noun:
• 打工 (daa2 gung1) → 打過工 (daa2 gwo3 gung1) 'worked before'
• 睇戲 (tai2 hei3) → 睇過戲 (tai2 gwo3 hei3) 'watched a movie before'

6. Disambiguation
Do not confuse experiential 過 with its other grammatical roles:
• Comparative: 高過佢 (gou1 gwo3 keoi5) 'taller than him'
• Iterative: 寫過 (se2 gwo3) 'rewrite / write over again'
• Main Verb / Direction: 過海 (gwo3 hoi2) 'cross the harbour'