Reciprocal “do to each other”
V-ますstem + 合う
Open details
Form: V-ますstem + 合う（話し合う／助け合う／見つめ合う）
Use when: two or more parties do the action mutually.
Note: 会う（to meet） and 合う（to fit/match/each other） are different kanji.
“Think/act as if” (but actually not)
mistaken belief / intention
Open details
Forms: 普通形 + つもりだ ／ N + の + つもりだ ／ V-た + つもりだった
Use when: speaker/subject believes something about intention or fact, but reality differs.
Nuance: for people, can sound critical (“彼は専門家のつもりだ”). For your own mistake, use V-たつもりだったが….
Habit with motion verbs
commute / regular trips
Open details
Form: （行く／来る／通う／帰る など）+ ている
Use when: habitual movement（毎週図書館に通っている）; phone reports can mean “has gone and is there” (今、銀行に行っています).
Contrast: progressive action vs. resultant state depends on context/time words.
Renyō-chūshi: stem-linking
formal sequence / narrative
Open details
Forms: V-ますstem + 、／ i-adj（〜く）+ 、／ na-adj・N + で、
Use when: formal writing / reports to chain actions without て; creates a crisp, concise rhythm.
Register: written/announcer-like; everyday speech prefers 〜て.
Nostalgic “used to …”
recollection of past habit
Open details
Form: V-た + ものだ ／ （i/na-adj + かった／だった + ものだ）
Use when: look back with feeling on repeated actions/states in the distant past.
Nuance: not for very recent past; often with よく／昔は／子どものころ.
1) 〜合う — do to/with each other
Attach 合う to the verb stem to show reciprocity between people/things.
Form: V-ますstem + 合う
Common: 助 け合う／話 し合う／向 き合う／支 え合う
となりの
In the shopping district, residents help each other prepare the festival.
We exchanged ideas and made a better plan.
となりに
We sat side by side and talked facing each other.
Common pitfall: needs at least two parties; for “fit/match well,” use 合う with a noun（サイズが合う）not this reciprocal pattern.
2) 〜つもりだ（実際とは異なる） — think/act as if; mistaken belief
Express the subject’s belief or intention that doesn’t match reality. Also used self-referentially for “I thought I had … but …”.
Forms: 普通形 + つもりだ ／ N + の + つもりだ ／ V-た + つもりだった
Variants: 〜つもりはない（no intention）／ 〜だったつもりだ（insistive; can sound self-justifying）
かれは
He fancies himself an expert, but he doesn’t grasp the basics.
I thought I’d sent it, but I had the wrong address.
これは
It was meant as a joke, but I upset them.
Caution: Saying “〜のつもりだ” about others can sound snarky; be careful in business contexts.
3) （移動動詞）〜ている — habitual trips / resultant state
With motion verbs, 〜ている often means a habit (go regularly). In reports, it may mean “has gone and is (there).”
Form: 行く／来る／通う／帰る／出る + ている
Signals: time words（毎日・週末）→ habit／ “今・ただいま” in calls → resultant state.
毎朝
I commute to the office by bicycle every morning.
週末は よく
On weekends I often go to art museums.
「山田さんは？」「
“Where is Yamada?” “He’s gone to the post office (and is there now).”
Contrast: progressive “is going now” → usually 行っているところだ／向かっている to avoid confusion.
4) 連用中止 — stem-linking for formal sequence
Link clauses by using the 連用形（ます-stem / 〜く / 〜で）+ comma. Sounds concise and written.
Forms: V-ますstem + 、／ i-adj（〜く）+ 、／ na-adj・N + で、
Register: reports, essays, news. Casual speech → 〜て／〜し.
I opened the door, entered the room, and turned on the light.
The weather was calm, the wind light—perfect for a walk.
We reviewed the budget, revised the plan, and made a fresh start.
Note: avoid overuse in casual emails; it can sound stiff or literary.
5) 〜たものだ — used to… (nostalgia)
Recalls repeated actions/states in the distant past, often with emotion.
Form: V-た + ものだ ／ （na-adj + だった + ものだ ／ i-adj + かった + ものだ）
When I was a kid, I used to play outside until sunset.
若いころは よく
When I was young, I could eat spicy food without trouble.
My grandpa used to tell the same old stories.
Softener: add なあ for a reflective tone（「よく 通 った ものだなあ」）.
Quick contrasts & pitfalls
- 〜合う = mutual action. For simple cooperation without reciprocity, consider 協力する.
- 〜つもりだ vs 予定だ: 予定 = objective plan; つもり = one’s intention/belief. “Mistaken belief” often uses V-たつもりだった.
- （移動動詞）〜ている: be careful—今、駅に行っています can mean “has gone and is at the station,” not “is on the way”. Use 向かっています for “on the way”.
- 連用中止 = written/formal; overuse in casual emails may sound stiff. Mix with 〜て to keep natural flow.
- 〜たものだ = distant past + emotion; for neutral past habit use よくV-た or 〜ことがあった.
