anitati ha syakaizin ni natte kara totemo <ruby><rt>isoga</rt></rubysiku narimasita.

After my older brothers became working adults, they became very busy.

Breakdown of anitati ha syakaizin ni natte kara totemo <ruby><rt>isoga</rt></rubysiku narimasita.

• は: topic particle
• とても: very
• なる: to become
• に: target particle
• 〜て から: after doing
• 兄あにたち: older brother (plural)
• 社会人しゃかいじん: working adult
• 忙いそがしく: busily

Questions & Answers about anitati ha syakaizin ni natte kara totemo <ruby><rt>isoga</rt></rubysiku narimasita.

Why is 兄 followed by たち? What does 兄たち mean exactly?

兄 means “older brother.” Adding たち makes it plural or group-like, so 兄たち means:

• “my older brothers” (more than one)
  or
• “my older brother and the people associated with him” (e.g., his wife, etc., depending on context)

In most textbook examples, you can simply understand 兄たち as “my older brothers.”

Why is it 兄たち and not お兄さんたち?

Japanese often uses different words depending on whether you are talking about your own family or someone else’s:

• Talking about your own older brother to an outsider: usually 兄 (plain, neutral), not お兄さん (which sounds more respectful).
• Talking directly to an older brother or about someone else’s: お兄さん is common and polite.

So 兄たち here reflects talking about one’s own older brothers in a neutral, non-honorific way, which is normal in narratives or essays about your own family.

What does 社会人 mean here? Is it just “adult”?

社会人 literally means “member of society,” but in modern Japanese it almost always means:

a working adult (typically someone who has finished school and started a full-time job)

It’s not just “adult” in the biological or legal sense; it focuses on the social role as a worker.

Compare:

• 大学生 – university student
• 社会人 – working adult (no longer a student; participating in the workforce)

So the sentence is talking about the time when the brothers started working in society as adults (got jobs), not simply when they turned 20.

Why is there a に after 社会人 in 社会人になって?

The pattern is:

• Noun + に + なる = “to become (Noun)”

So:

• 社会人になる = “to become a working adult”
• 先生になる = “to become a teacher”
• 有名人になる = “to become a famous person”

The に marks the resulting state you change into. That’s why it must be 社会人に なる, not just 社会人 なる.

What is the function of なってから? How is 〜てから used?

〜てから means “after doing ~” and introduces the starting point in time for something that follows.

Pattern:

• (verb in て-form) + から + main action

In this sentence:

• 社会人になってから = “after (they) became working adults”

So the structure is:

• 兄たちは – topic: “(as for) my older brothers”
• 社会人になってから – time frame: “after they became working adults”
• とても忙しくなりました – main statement: “(they) became very busy”

It implies that before they became working adults, they weren’t that busy, and from that point on they became (and are) busy.

Why is it 忙しく and not 忙しい in とても忙しくなりました?

With い-adjectives and なる (“to become”), you must use the adverbial / 連用形 (ren’yōkei) form, which for い-adjectives is made by replacing 〜い with 〜く:

• 忙しい → 忙しく
• 高い → 高く
• 寒い → 寒く

Then:

• 忙しくなる = “to become busy”
• 高くなる = “to become expensive / high”
• 寒くなる = “to become cold”

So:

• とても忙しくなりました = “(they) became very busy”

Using 忙しいなりました would be ungrammatical.

What nuance does なりました have here? Is it “became” or “have become” (and are still busy)?

Japanese 〜ました covers both simple past and present perfect-like meanings, depending on context.

忙しくなりました can mean:

• “(they) became busy”
  or
• “(they) have become busy (and are now busy)”

Because it’s paired with 〜てから (“ever since they became working adults”), the natural interpretation is:

“Ever since they became working adults, they have become very busy (and are still busy now).”

So it describes a change that occurred in the past and typically continues into the present.

Why is it 兄たちは and not 兄たちが?

は marks the topic (“as for X…”), while が marks the grammatical subject, often introducing new or focused information.

• 兄たちは社会人になってから…
  = “As for my older brothers, after they became working adults, they became very busy.”
  → Focus is on what happened to them, as the topic of the sentence.

If you said:

• 兄たちが社会人になってからとても忙しくなりました。

it would be possible, but the nuance would be more like emphasizing that it was the older brothers who did this (as opposed to someone else), which is less natural here without specific contrast.

For neutral, descriptive narration, 兄たちは (topic) is standard.

Could you rewrite the core pattern of 忙しくなりました in a simple formula?

Yes. For い-adjectives:

1. Take the dictionary form: 忙しい
2. Change 〜い to 〜く: 忙しく
3. Add なる (“become”) and conjugate as needed: 忙しくなる / 忙しくなりました

General formula:

(い-adjective in 〜く form) + なる = “to become (adjective)”

Examples:

• 暑い → 暑くなる → 暑くなりました (“It became hot.”)
• きれい（な） → きれいになる → きれいになりました (“It became clean / pretty.”)
  (for な-adjectives, use 〜になる directly)

Could 社会人になって、とても忙しくなりました be used instead of 社会人になってから…? What’s the difference?

You can say:

• 社会人になって、とても忙しくなりました。

This is grammatical and means roughly the same, but there is a nuance difference:

• 社会人になってから…
  → Emphasizes “from the time they became working adults onward” (a clear starting point, ongoing period).

• 社会人になって、…
  → More like “they became working adults, and (as a result) they became very busy”; it links two events in order, but doesn’t highlight the ongoing time span as strongly.

In many contexts, both are acceptable, but 〜てから is more explicit about the “ever since then” feeling.