5 Essential Grammar Patterns to Express “Something Happens Immediately” ②
Table of Contents
1. 5 Essential Grammar Patterns to Express “Something Happens Immediately”
2. Grammar Comparison
3. Aが早いかB
4. Aかと思ったらB
5. Aとたん（に）B
6. Let’s Compare
7. Summary
8. Similer Articles
9. Comment
Q: What’s the difference between the grammar patterns “〜そばから,” “〜てすぐ,” “〜が早いか,” “〜かと思ったら,” and “〜とたん”?
A: All of these expressions show that one action happens right after another. However, each has different nuances and usage. In the previous section, we focused on “〜そばから” and “〜てすぐ.” This time, let’s take a closer look at “〜が早いか,” “〜かと思ったら,” and “〜とたん.”
If you want to know the difference between “〜そばから” and “〜てすぐ” in more detail,
please read this article.
Grammar Comparison
Let’s start by reviewing the overall differences in a summary chart.
| Expression | Meaning | Features |
|---|---|---|
| A そばから B | As soon as A happens, B happens again | B (often the same thing) occurs repeatedly right after A; often implies A’s effort is wasted. |
| A てすぐ | Immediately after A | B happens right after A; expresses the next action in a neutral way. |
| A が早いか B | The moment A happens / almost simultaneously | A and B occur nearly at the same time; emphasizes simultaneousness. |
| A かと思ったら B | Just when A happened | B (often an unexpected development) occurs immediately after A. |
| A とたん（に）B | Right after A / the moment A ends | B (often surprising or unanticipated) occurs the very moment A ends. |
Aが早いかB (JLPT N1)
[Meaning]
B happens almost at the same time as A happens
[Rule]
[V] Verb dictionary form + が早いか
[Examples]
ベルが鳴るが早いか、生徒たちは教室を飛び出しました。
As soon as the bell rang, the students rushed out of the classroom.
玄関のドアを開けるが早いか、母が「おかえり」と言いました。
No sooner had the front door opened than my mother said “Welcome home.”
A happens, and B follows almost simultaneously — this structure expresses an immediate sequence of actions.
It emphasizes the speed and suddenness of the events, and is most often used in written language.
[Examples]
娘は家に帰るが早いか、またどこかへ出かけて行きました。
As soon as my daughter came home, she went out again.
⇒ She went out immediately after returning home, without pausing.
電車のドアが開くが早いか、みんな一斉に電車に乗りました。
No sooner had the train doors opened than everyone boarded at once.
⇒ Emphasizes that passengers boarded the train the very instant the doors opened.
Aかと思ったらB (JLPT N2)
[Meaning]
Indicates that an unexpected development B follows immediately after A happens
[Rule]
[V] Verb past form + かと思ったら
[Examples]
子供は帰ってきたかと思ったら、すぐ出かけてました。
Just when the child got home, they immediately went out again.
ようやく雨が止んだかと思ったら、また降り出しました。
Just when the rain finally stopped, it started falling again.
“A かと思ったら B” expresses that an unexpected development or change (B) occurs immediately after A happens.
[Examples]
注意して静かになるかと思ったら、子供達はまた騒ぎ始めました。
Just when I thought the children would quiet down after being scolded, they started making noise again.
⇒ This shows an unexpected turn of events: instead of calming down, they started making noise again.
大きな仕事が終わったかと思ったら、すぐに新しいプロジェクトが始まりました。
Just when I thought the big project was over, a new one started right away.
⇒ Emphasizes the surprise of having a new task begin immediately after finishing the last one.
This expression is not only used to show surprise, but also often appears when there is a shift in emotion between A and B.
A: Something the speaker was hoping or waiting for
B: A disappointing or surprising event that goes against that expectation
For this reason, it is often used with adverbs like “ようやく” (finally) or “やっと” (at last), which emphasize the sense of effort or anticipation followed by a letdown.
[Examples]
ようやく桜が咲いたかと思ったら、もう散ってしまいました。
Just when the cherry blossoms finally bloomed, they had already fallen.
⇒ A: The cherry blossoms bloomed (expectation)
B: They quickly fell (disappointment)
やっと電車が来たかと思ったら、満員でした。
Just when the train finally arrived, it was full.
⇒ A: The train arrived (expectation)
B: It was too full to get on (letdown)
Aとたん（に）B (JLPT N3)
[Meaning]
As soon as A happened, B occurred at that very moment
[Rule]
[V] Verb past form + とたん（に）
[Examples]
立ち上がったとたん、めまいがしました。
As soon as I stood up, I felt dizzy.
大きな雷が鳴ったとたんに、子供が泣き出しました。
The moment a loud thunder sounded, the child started crying.
“A とたん（に）B” is a grammar pattern that means “the moment A happened, B (which was unexpected) occurred immediately.”
The B part often describes one of the following:
Physical reactions (e.g., feeling dizzy, tears coming out)
Reflexive responses (e.g., being surprised, bursting into tears)
Natural phenomena (e.g., it starts to rain, thunder roars)
[Examples]
この曲を聞いたとたんに、涙が出てきました。
The moment I heard the song, tears welled up in my eyes.
⇒ Shows that emotions surged the moment the song was heard.
父が怒ったとたん、息子は静かになりました。
As soon as my father got angry, my son became quiet.
⇒ Indicates the son reacted immediately to the father’s anger.
Let’s Compare
Let’s start with a quick review of how the five grammar patterns are used:
① AそばからB：
Even if A is done, B — something similar — happens again right away.
⇒ Implies that A’s action is repeatedly undone or wasted.
② AてすぐB：
Indicates immediate time or distance.
⇒ States in a neutral way that B happened right after A.
③ Aが早いかB：
Describes a rapid sequence where B happens almost at the same moment as A.
⇒ Emphasizes that A and B occurred nearly simultaneously; often used in written language.
④ Aかと思ったらB：
An unexpected development or change (B) follows right after A.
⇒ Especially when A involves effort or expectation (e.g., “finally”), it conveys surprise or disappointment.
⑤ Aとたん（に）B：
Right at the moment A happens, an unexpected change (B) occurs.
⇒ B is often a physical reaction, natural phenomenon, or reflexive response.
All five of these grammar patterns share the common point that “B happens immediately after A,” but each differs in nuance and the situations in which it is used.
The key is to look at what happens in B and choose the expression accordingly.
Let’s compare them using “帰る (to go home)” as A and changing B:
帰ったそばから、またすぐ出かけました。
⇒ The word “また (again)” emphasizes repetition. It gives the impression that “going home” was pointless.
帰ってすぐ出かけました。
⇒ Describes the time order neutrally, simply stating that one thing followed another.
帰ったかと思ったら、また出かけました。
⇒ Conveys surprise, as in “I didn’t expect them to go out again.”
These three sentences all feel natural because the content of B fits the nuance of each grammar pattern.
However, the following two examples are unnatural in meaning:
帰るが早いか、出かけました。
⇒ It’s unrealistic for “going home” and “going out” to occur as two instantaneous actions by the same person.
帰ったとたん、出かけました。
⇒ “Going out” is not a physical reaction or reflex, so it doesn’t fit well with “とたん,” which typically follows such events.
As you can see, even if the structure “B happens right after A” is the same, the nature of B determines which grammar pattern is appropriate.
To use them correctly, it’s important to pay attention to the nature of the event in B and whether it reflects any emotion from the speaker.
Summary
| Expression | Meaning | Key Point |
|---|---|---|
| A そばから B | As soon as A happens, B happens again | Even if A is done, B — something similar — happens again right away. Implies that A’s action is repeatedly undone or wasted. |
| A てすぐ | Immediately after A | Neutral expression indicating that B happened right after A in terms of time or distance. |
| A が早いか B | The moment A happened / Almost simultaneously | Emphasizes that A and B happened almost at the same time. Often used in written language. |
| A かと思ったら B | Just when A happened | B — an unexpected result or change — happens right after A. Often used when A is something anticipated or hoped for, and B brings surprise or disappointment. |
| A とたん（に）B | Right after A / The instant A happened | B — an unexpected change — happens the moment A occurs. B is often a physical reaction, natural phenomenon, or reflexive response. |
Similer Articles
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