# HSK 4 Grammar: Prepositions of Time and Place (自, 当, 由, 随着, 等) | HSKReady Canonical: https://hskready.app/en/grammar/hsk-4-prepositions-78e0dc1a59 Language: en Content ID: web-grammar-hsk-4-prepositions-78e0dc1a59 HSK levels: 4 Updated: 2026-10-23T04:56:47.758Z Scope: published website educational content; full vocabulary, question bank and mock exams remain in the app. Learn how to use the Chinese prepositions 自, 当, 由, 随着, and 等 to introduce time, location, and developing conditions in HSK 4 grammar. Grammar [HSK 4 · Word classes › Prepositions › Introducing time or place](https://hskready.app/en/grammar/hsk-4#hsk-4-g014) # HSK 4 Prepositions Introducing Time and Location: 自, 当, 由, 随着, and 等 This HSK 4 outline item covers 自、当、由、随着 and 等. 自 and 由 can mark origins or routes; 当 frames a time or event; 随着 can describe parallel change or accompaniment; and 等 sets a time or condition for the next action. Their collocations and register differ. 自 / 由 starting time or place verb phrase Example sentence 这趟列车自北京出发，开往上海。 Zhè tàng lièchē zì Běijīng chūfā, kāiwǎng Shànghǎi. This train departs from Beijing and heads to Shanghai. Correct: 自 introduces the spatial point of departure in a formal announcement style. **Read the full explanation and examples** ## Overview: Beyond Basic Time and Place Markers In early Chinese study, learners rely heavily on 在 (zài) to mark location and 从 (cóng) to mark a starting point in time or space. In the Level 4 grammar syllabus of the 2025-11 HSK outline, the preposition category expands to include five specific items that introduce time, location, or temporal backgrounds: 自 (zì), 当 (dāng), 由1 (yóu), 随着 (suízhe), and 等1 (děng). Note that level labels reflect this specific syllabus document rather than a guarantee about which exam version a given test center currently administers. Although the syllabus groups these five words together under prepositions introducing time and location, they are not interchangeable. Each controls a distinct relationship between a temporal or spatial reference point and the main action, and they differ sharply in register and sentence structure. ## Marking Formal Origins and Routes: 自 and 由 自 often sounds concise or written; 由 is also common in route and direction expressions. The outline labels the origin use 由1. Here we illustrate it with a journey from Guangzhou, without assuming that every dictionary uses the same numbering or that 由 is restricted to announcements. 自 / 由 starting time or place verb phrase 自 introduces a starting time or place. Time phrases commonly use 自……起 or 自……开始; spatial examples include 自北京出发 and 自北京来. The following verb is not restricted to two syllables. 这趟列车自北京出发，开往上海。 Zhè tàng lièchē zì Běijīng chūfā, kāiwǎng Shànghǎi. This train departs from Beijing and heads to Shanghai. Correct: 自 introduces the spatial point of departure in a formal announcement style. 新规定自下个月起正式实行。 Xīn guīdìng zì xià gè yuè qǐ zhèngshì shíxíng. The new regulation will formally take effect starting next month. Correct: 自 pairs with 起 to mark a formal starting point in time. 由1 also introduces a point of origin, route, or source in space, time, or state transitions. Compared with 自, 由 is especially common when describing physical routes, directional transitions (such as moving from one city or stage to another), or starting points in itineraries. 代表团将于明日由广州前往香港。 Dàibiǎotuán jiāng yú míngrì yóu Guǎngzhōu qiánwǎng Xiānggǎng. The delegation will travel from Guangzhou to Hong Kong tomorrow. Correct: 由 marks the starting location along a planned travel route. ## Framing Points and Conditions in Time: 当 and 等 当 frames an event as a time reference. 等 introduces the time or condition for a following action; the outline labels this use 等1, distinct from the listing use taught elsewhere. 当 time or event clause （时 / 的时候）， main clause 当 commonly pairs with 时 or 的时候, as in the classroom example. These endings are not compulsory: 当你需要帮助，我会支持你 is also natural. The event clause must supply a clear time reference; its grammatical completeness does not depend on one closing word. 当我走进教室的时候，大家都在安静地看书。 Dāng wǒ zǒujìn jiàoshì de shíhou, dàjiā dōu zài ānjìng de kànshū. When I walked into the classroom, everyone was quietly reading. Correct: 当 pairs with 的时候 to frame the time when the background action was happening. 等 time point or condition to be met （以后）， main clause 等 often occurs in conversation. It can introduce a time point (等到明天) or a condition (等你有空). 再 or 才 may clarify the sequence, but they are not required: 等你有空，我们聊聊 is complete. The condition need not be the completion of an action. 等雨停了，我们再出去散步吧。 Děng yǔ tíng le, wǒmen zài chūqù sànbù ba. Let's wait until the rain stops before going out for a walk. Correct: 等 introduces the temporal condition that must be met before the action with 再 takes place. ## Tracking Parallel Change Over Time: 随着 In the temporal pattern here, 随着 links an unfolding condition with a corresponding situation. 随着天气变暖 makes the change explicit. The connection may be correlation or accompaniment rather than proof of causation. Other uses can take an ordinary noun, as in 随着音乐跳舞. 随着 phrase showing change or development ， subject resulting change or state 随着天气变暖，公园里的游客越来越多了。 Suízhe tiānqì biàn nuǎn, gōngyuán lǐ de yóukè yuèláiyuè duō le. As the weather gets warmer, there are more and more visitors in the park. Correct: 随着 introduces a changing condition (weather warming) that leads to a result. Notice how the phrase after 随着 in the example above describes a transition (the weather becoming warmer), and the main clause describes a corresponding shift (visitors becoming more numerous). ## Key Contrasts and Common Learner Errors - Register: 从 is the usual broad starting-point marker. 自 is often more written or concise; 由 also works naturally in expressions such as 由东向西 and 由小到大. Choose a familiar collocation rather than reserving both words only for official notices. - 当 frames when something happens, including in a future situation. 等 focuses on reaching the time or condition for the next step. Neither is limited solely by past-versus-future tense. - With temporal 随着, make the intended transition clear. 随着春天的到来 explicitly means “with spring’s arrival”. This does not create a universal ban on noun objects in accompaniment expressions. To describe spring’s arrival plainly, either state 春天到了 or use the explicit phrase 随着春天的到来. These are clear ways to connect the season with the blooming flowers. 春天到了，公园里的花都开了。 Chūntiān dào le, gōngyuán lǐ de huā dōu kāi le. Spring has arrived, and the flowers in the park have all bloomed. A simple statement of spring’s arrival. The next example frames the same event with 随着 and an explicit arrival phrase. 随着春天的到来，公园里的花都开了。 Suízhe chūntiān de dàolái, gōngyuán lǐ de huā dōu kāi le. With the arrival of spring, the flowers in the park have all bloomed. 随着春天的到来 explicitly names the arrival process; it is an alternative to 春天到了, not a rule that 随着 must always contain a particular change word. Quick check: ask what relationship you intend—time, parallel change or accompaniment. Choose wording that makes that relationship clear, rather than mechanically searching for 的变化 after every 随着. ## Frequently asked questions **Can I always replace 从 with 自 or 由 in daily conversation?** Not always: 从、 自 and 由 overlap in some origin expressions but have different collocations. 从北京来 is a familiar conversational model; 由东向西 is also natural. Register is one factor, not a rule that 由 is forbidden when speaking with friends. **Can 当 be used without 时 or 的时候?** Yes. 当我走进教室的时候 gives an explicit time frame, while 当你需要帮助，我会支持你 works without 时. Choose the form that fits the rhythm and meaning; a time clause is not automatically incomplete without a closing marker. **Why is 等 listed as a preposition here when it usually means the verb 'to wait'?** 等 developed its temporal meaning ('when' or 'by the time') from the verb 'to wait.' In sentences like 等雨停了我们再走, the subject is not necessarily actively standing around waiting; 等 simply marks the time condition ('once the rain stops') for the main clause. **Source**[hsk.cn-bj.ufileos.com · PDF page 395](https://hsk.cn-bj.ufileos.com/3.0/%E6%96%B0%E7%89%88HSK%E8%80%83%E8%AF%95%E5%A4%A7%E7%BA%B21219.pdf#page=395) ## Continue in the app Full mock exams are available in HSKReady. [![Download on the App Store](https://hskready.app/download-on-app-store-black.svg)Download on the App Store](https://apps.apple.com/us/app/id6791916440?l=en)[![Get it on Google Play](https://hskready.app/get-it-on-google-play.svg)Get it on Google Play](https://play.google.com/store/apps/details?id=com.curiolab.hskready&hl=en) [HSKReady App](https://hskready.app/en/app)