在 — Temporal: 在 + a time word sites the event at that point on the timeline.

grammar → 在

TSUMUGU · TBCL 2 (est.) · 語法

在 grammar point · tier 1 · temporal 在 (at a point in time)

· zài

Temporal: 在 + a time word sites the event at that point on the timeline.

Hook inherited from 在.

Temporal

框 · Frame

[subj] 在 [time (…的時候)] [verb (+ obj)]

觸 · Trigger

You want to fix when an event happens.

序 · The move

1Name the subject, then 在.Is what follows 在 a time word, not a place and not a verb?

2Put the time straight after 在; close a clause-length time with 的時候.A single point or span is named; a longer 'when …' clause ends in 的時候.

3Set the time phrase before the main verb, then the verb.The 在-time block sits ahead of the action, not trailing it.

例 · Examples

1他在at (a time)聖誕節Christmas的時候at the time of, when去go美國America。

He goes to America at Christmas.

界 · Boundary

在1 locative (他在學校)

What follows 在 splits them: a time word means at that moment (在聖誕節); a place noun means located there (在學校). Same 在, one stakes a moment, one stakes a spot.

在2 progressive (他在吃飯)

A verb after 在 means the action is going on now (在吃飯); a time word after 在 fixes when a separate verb happens (在週末去).

bare time word, no 在 (他週末去)

A plain time adverb stands alone before the verb (週末去); 在 only fronts it to stress the moment or to close a 的時候 clause. Dropping 在 stays correct; adding 在 to a place or a verb does not.

他去美國在聖誕節的時候。 → 他在聖誕節的時候去美國。

他是在聖誕節去美國。 → 他在聖誕節去美國。

他在去美國聖誕節。 → 他在聖誕節去美國。

English 'at/on/in' before a time is always required ('at Christmas'); Chinese 在 here is optional and the time phrase precedes the verb, never trailing it as in 'goes to America at Christmas'.