Past tenses
Mandarin has no past tense — verbs never change. Instead it marks aspect: whether an action is completed (了), experienced (过), or ongoing (着), while plain time words (昨天 "yesterday") do the actual "when".
Time words carry the tense
Often the past needs nothing but a time word:
我昨天很忙 wǒ zuótiān hěn máng — "I was busy yesterday" 她以前住在伦敦 tā yǐqián zhù zài Lúndūn — "she used to live in London"
No marker at all. If European instincts tell you to conjugate, put a time word there instead.
The three aspect markers
| marker | means | example |
|---|---|---|
| 了 le | action completed | 我买了三本书 wǒ mǎi le sān běn shū — "I bought three books" |
| 过 guo | ever experienced (at least once) | 我去过中国 wǒ qù guo Zhōngguó — "I've been to China (before)" |
| 着 zhe | state ongoing / resulting | 门开着 mén kāi zhe — "the door is (stands) open" |
了 le — completion, not past
了 means "done", which is usually past but doesn't have to be:
吃了饭我们就走 chī le fàn wǒmen jiù zǒu — "once we've eaten, we'll leave" (future!)
The classic 了 traps
| trap | wrong | right |
|---|---|---|
| 了 with 没 | 我没去了 ✗ | 我没去 wǒ méi qù — "I didn't go" (没 already denies completion) |
| 了 on past habits | 我小时候每天游泳了 ✗ | 我小时候每天游泳 — "as a kid I swam every day" (habit, nothing "completed") |
| 了 on past states | 昨天很冷了 ✗ | 昨天很冷 zuótiān hěn lěng — "yesterday it was cold" |
| 了 with 是/在/认识 etc. | 他是老师了(meaning "was") ✗ | 他以前是老师 — "he was a teacher before" |
Rule of thumb: 了 goes on bounded events ("bought three books", "ate lunch"), not on descriptions, habits, or states.
Two 了s
Verb-了 marks completion; sentence-final 了 marks a new situation:
下雨了 xià yǔ le — "it's (started) raining" · 我三十岁了 wǒ sānshí suì le — "I'm 30 now"
Both can co-occur: 我吃了饭了 — "I've eaten (so stop offering)."
过 guo — "have you ever…?"
过 is for life experience, detached from any particular time:
你吃过北京烤鸭吗？nǐ chī guo Běijīng kǎoyā ma? — "Have you ever had Peking duck?" 吃过 chī guo — "I have" · 没吃过 méi chī guo — "never" (过 survives after 没, unlike 了)
Compare: 我去了中国 "I went to China (that trip happened)" vs 我去过中国 "I have been to China (at some point)".
着 zhe — frozen states
着 describes a state left behind by an action — good for positions and background:
墙上挂着一张地图 qiáng shang guà zhe yī zhāng dìtú — "a map hangs on the wall" 她笑着说 tā xiào zhe shuō — "she said, smiling" (background action)
Beginners need to recognize 着 more than produce it.
The takeaway
Stop asking "how do I put this verb in the past?" — ask "is the action done (了), experienced (过), or a state (着) — or does a time word cover it?" No conjugation tables, no irregular pasts; the price is learning where 了 does not go.
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