正在

Mandarin does not mark tense on verbs the way European languages do. Instead, it uses aspect — grammatical markers that signal the internal structure of an event: whether it is complete (了 le), experienced (过 guò), ongoing (正在 / 在 / 着), or still relevant. 正在 is the most explicit progressive marker, unambiguously flagging that an action is in progress at the moment of speaking.

The construction is simple: 正在 + Verb (+ 呢). 正在 sits before the verb; the optional sentence-final particle 呢 at the end reinforces the progressive reading. No tense suffix on the verb. No auxiliary verb. The marker carries the whole grammatical load, and the verb stays in its base form.

Understanding 正在 fully requires understanding two related markers: 在, which does the same job with less emphasis, and 着, which marks a different kind of ongoing state. All three are frequently encountered; all three are often confused by learners. The distinctions between them are real and worth mastering.

These three markers all relate to ongoing situations, but they encode different aspects of that ongoingness. The distinctions are not interchangeable.

正在 + V marks an action as actively in progress at the moment of speaking. The speaker and the action are simultaneous. This is the fullest, most explicit progressive signal: it cannot be used for states that are merely true (you would not say 他正在知道 for "he knows," because knowing is not an activity). Use 正在 when the action is dynamic and is happening right now.

在 + V does exactly the same work as 正在, with slightly less emphasis. In most spoken contexts, 在 alone is more natural and colloquial; 正在 carries a trace of formality or deliberate focus. 我在吃饭 and 我正在吃饭 are both grammatical and nearly synonymous, but 在 is more typical in casual speech.

V + 着 zhe is fundamentally different. 着 marks a resultant state or ongoing condition — the continued existence of the result of an action, not the action itself. 门开着 (the door is open, standing open — the result of having been opened) versus 他在开门 (he is in the process of opening the door). A sign posted on a wall is 挂着 (hanging, in the state of having been hung); a person hanging a sign is 在挂. The same verb root, radically different grammatical meaning.

正在 and 在 are not restricted to the present. When combined with a past time expression, they produce the past progressive: an action that was in progress at a specific past moment. The aspect marker does not change; the time frame is set by the adverb.

The key time frames for past progressive: 那时候 nà shíhou (at that time), 刚才 gāngcái (just now, a moment ago), 昨天 zuótiān (yesterday) + a time point. Examples: 他那时候正在睡觉 (he was sleeping at that time), 我刚才在开车 (I was driving just now), 他们昨天下午在开会 (they were in a meeting yesterday afternoon).

This is one of the places where Mandarin's aspect-based grammar is elegantly economical: the same marker 正在 handles present and past progressive without modification. Context and time words do all the work of tense placement.