N4 · Unit 12
Lesson 45Continuing change and multiple reasons
Describe change from past to present or present to future, give multiple reasons, and express proportional change.
What you learn
Describe change from past to present or present to future, give multiple reasons, and express proportional change.
Learning points
- Developing change
- Multiple reasons
- Proportional change
Why this lesson comes now
This lesson connects what you can already say to a new way of expressing it. Hear the key sentences, understand the structure, then use it in a real situation.
Your next step
Listen to the key sentences, understand the pattern, finish the examples and vocabulary, then continue to the next lesson.
Open the interactive lessonCore pattern
動詞て + きました / いきます（変化） ・ 非意志動詞て + きました（出現） ・ 普通形 + し、普通形 + し ・ 動詞ば形 + 動詞基本形 + ほど / い形容詞ければ + い形容詞 + ほどBeginner explanation
Use 〜てきました for a change viewed from the past up to now, and 〜ていきます for a change continuing from now into the future. 〜てきました can also mark the onset of a state such as rain or fatigue. 〜し、〜し lists multiple reasons or features. 〜ば〜ほど expresses that the more one degree changes, the more a related result changes.
Understand these sentences first
- 最近、外国からの 観光客が 増えて きました。saikin, gaikoku kara no kankōkyaku ga fuete kimashita
Recently, the number of visitors from abroad has been increasing.
- これからも 日本語を 勉強して いきます。kore kara mo Nihongo o benkyō shite ikimasu
I will continue studying Japanese from now on.
- 雨が 降って きました。ame ga futte kimashita
It has started to rain.
- この 本は 読めば 読むほど おもしろいです。kono hon wa yomeba yomu hodo omoshiroi desu
This book becomes more interesting the more you read it.
Core vocabulary
- 増えますふえますincrease
- 減りますへりますdecrease
- 続きますつづきますcontinue
- 進みますすすみますadvance
- 人口じんこうpopulation
- 品質ひんしつquality
- 交通こうつうtransport
- 手軽てがるeasy; convenient
Grammar, one point at a time
Development from the past to now: Vてきました
Vて + きましたLooking back from the present reference point, this form marks an action continuing up to now or a quality, quantity, or state developing into its current form. きました here describes temporal development rather than physical movement.
Examples
- この町は 10年間で 大きく 変わってきました。This city has changed greatly over the past ten years.
- 日本語を 3年間 勉強してきました。I have studied Japanese for three years up to now.
- 利用者が 少しずつ 増えてきました。The number of users has gradually increased.
Development from now onward: Vていきます
Vて + いきますWith now as the starting point, this form marks an action continuing or a state changing into the future. It often appears with これから, 今後, or だろう／でしょう. A trend prediction still needs a source and assumptions.
Examples
- これからも 日本語を 勉強していきます。I will continue studying Japanese.
- 今後、人口構成は 変わっていくでしょう。The population structure will probably continue to change.
- 使い捨ての 容器を 減らしていきます。We will continue reducing disposable containers.
A state has begun to emerge: Vてきました
非意志的な変化 Vて + きましたThis use marks rain, hunger, fatigue, cold, or another change beginning and reaching the current moment. It normally takes a non-volitional change. A deliberate activity continued up to now belongs to the preceding development use.
Examples
- 雨が 降ってきました。It has started to rain.
- おなかが すいてきました。I am starting to feel hungry.
- 少し 寒くなってきました。It is starting to get a little cold.
List multiple reasons or features with ～し、～し
普通形／礼貌形 + しし can link verbs, adjectives, and noun predicates to list reasons or features. Earlier subjects often take も to emphasize this too and that too. A single ～し can imply that other reasons also exist.
Examples
- 駅も 近いし、家賃も 手頃だし、この部屋に します。The station is close and the rent is reasonable, so I will take this room.
- 今日は 休みだし、天気も いいし、散歩に 行きたいです。It is a day off and the weather is good, so I want to take a walk.
- 時間も ないし、今日の 練習は ここまでです。We are also short on time, so today's practice ends here.
The more...the more: ～ば～ほど
Vば V辞書形ほど／Aければ Aいほど／NAなら NAなほどRepeat the same action or quality to show the following result changing as the first degree increases. This expresses correlation, not automatic proof of causation; real claims still need scope and conditions. Na-adjectives commonly use 便利なら便利なほど in speech and 便利であれば便利なほど in formal writing.
Examples
- 調べれば 調べるほど、条件の 違いが 分かります。The more you investigate, the clearer the differences in conditions become.
- この道具は 使えば 使うほど、便利さが 分かります。The more you use this tool, the more you appreciate its convenience.
- 説明は 短ければ 短いほど よいとは 限りません。An explanation is not necessarily better the shorter it is.
Turn particle phrases into noun modifiers with で／へ／から／まで／と＋の
N + で／へ／から／まで／と + の + NA phrase marking place, direction, origin, endpoint, or companion can take の to modify a following noun, as in 東京への便. At this stage, remember that に does not directly become にの. Use への when the meaning is directional, or keep a full verb modifier.
Examples
- 空港から 市内までの バスa bus from the airport to the city centre
- 東京への 便a service to Tokyo
- 母との 相談a discussion with my mother
- 母に 渡す プレゼントa present to give my mother
Expressions and situations
交通の便がいい means transport is convenient, not that any object has a good 便
便 read べん can mean convenience, and the fixed expression 交通の便がいい／悪い evaluates transport access. ホテルや交通の便 coordinates the hotel with transport convenience; it does not license ホテルの便がいい. 便 read びん is a different sense for a flight, service, or mail.
- この地域は 交通の便が いいです。This area has convenient transport.
- 大阪への 便は 1日に 6便あります。There are six services a day to Osaka.
ライトアップされています says a building or landmark is illuminated
ライトアップする means to illuminate a building, trees, or monument decoratively. The passive progressive ライトアップされています emphasizes the resulting illuminated state. For an ordinary room light, use 電気がついています.
- 橋が ライトアップされています。The bridge is illuminated.
- 部屋の 電気が ついています。The room light is on.
以前 can mean previously by itself or follow a reference point to mean before
As an adverb, 以前 can mean previously, as in 以前、ここに住んでいました. It can also follow a reference point in 入社以前, 結婚以前, or 入社する以前. Modern Japanese does not categorically ban preceding modifiers. When a numeric span could be ambiguous, prefer 10年前 or state exact dates.
- 以前、ここに 住んでいました。I used to live here.
- 入社する 以前に、日本語を 勉強しました。I studied Japanese before joining the company.
なんか here casually means somehow or kind of
Depending on context, なんか can mark a vague feeling, as in なんか変です. It is casual; formal reporting should state observations. It can also mean things like, as in ゲームなんかしません, which is a separate use.
- この音、なんか 変ですね。There is something odd about this sound.
- 休日は 読書なんかを します。On days off I do things such as reading.
似る commonly appears as 似ています but is not limited to that form
For a current resemblance, AはBに似ています is common. Other valid forms include 似た形, 全然似ていません, and 似れば似るほど. The comparison target takes に, and it is clearer to state whether shape, use, or sound is similar.
- この二つは 形が 似ています。These two have similar shapes.
- 飛行機に 似た 形です。It has a shape resembling an aeroplane.
アクセス can mean reaching a place or connecting to a digital resource
For transport, use 駅からのアクセスがいい. Digitally, use サイトにアクセスする or インターネットへのアクセス. For slow speed, interruption, or login failure, write 通信速度が遅い, 接続できない, or ログインできない rather than calling everything アクセスが悪い.
- 駅から 会場までの アクセスを 調べます。I will check access from the station to the venue.
- 現在、サイトに アクセスできません。The site is currently inaccessible.
軽く食べる means eat a little; 軽い食事 can also mean a less heavy meal
何か軽く食べる usually means to eat a little. 軽い物 or 軽い食事 can describe a small or less rich meal. The opposite is not categorically impossible: modern Japanese uses 胃に重い食事 or 重たい食事 for food that feels heavy on the stomach, but it is not a mechanical replacement in every use.
- 昼は 軽く 食べました。I ate a light lunch.
- 脂が 多くて、胃に 重い 食事でした。It was a rich meal that felt heavy on the stomach.
Choose だんだん, どんどん, ますます, or 年々 by the shape of change
だんだん emphasizes gradual change, どんどん rapid continuing progress, ますます an increasing degree, and 年々 change from year to year. For factual claims about population, temperature, or sales, also state territory, period, unit, and source; the adverb does not prove the trend.
- 利用者は 年々 増えています。The number of users is increasing year by year.
- 空が だんだん 暗くなってきました。The sky has gradually grown darker.
Environmental vocabulary spans everyday, scientific, and historical terminology
地球温暖化 describes long-term warming, while 気候変動 is broader. フロンガス is an everyday umbrella term for several fluorinated compounds. 環境ホルモン is a historical popular label; current formal material more often uses 内分泌かく乱化学物質. Do not treat an old umbrella term as one precise substance.
- 気候変動と 地球温暖化は、同じ 範囲の 言葉では ありません。Climate change and global warming do not cover exactly the same scope.
- 正式な 資料では、用語の 定義を 確認します。Check terminology definitions in formal material.
What you should be able to do
- Distinguish ～てきた from ～ていく on a timeline and write three examples of each with a reference time.
- Distinguish continued development from an emerging state with ～てきた and identify whether each verb is volitional.
- List at least two reasons with ～し、～し and compare the function with a て-form linkage.
- Build three ～ば～ほど sentences from verbs, i-adjectives, and na-adjectives without overstating causation.
- Use での, への, からの, までの, and との as noun modifiers and correct にの.
- Read one population or transport-project source and identify the statistical date, observed value, projection, project status, and unresolved points.
Culture and real use
Ask for dates and sources before accepting a trend: population decline and the maglev project cannot rely on old conclusions
Lesson 45 practises continuing change with declining births and a shrinking population. That direction is supported by statistics and projections, but declining births are not the only cause: total population also depends on births, deaths, and international migration. Japan's Statistics Bureau estimated the total population at 122.68 million on 1 August 2026. The 2023 national projection by the National Institute of Population and Social Security Research starts from the 2020 population and calculates 2021–2070 outcomes under several assumptions for births, deaths, and international migration, so it is a conditional projection rather than an observed future fact. The textbook's maglev sidebar is also an old plan description. Construction continues; the approved Shinagawa–Nagoya work plan says completion is scheduled for 2027 or later, while JR Central's 2025 material states that a 2027 opening cannot be achieved and that it cannot yet give a new opening date. The public course therefore retains the transport and change language while separating approved plans, construction status, and company expectations. Japan's environment ministry also says 環境ホルモン is a popular label for the scientific term 内分泌かく乱化学物質, so the course marks it as a historical popular term rather than one precise substance.
- 統計の 時点と 対象を 確認します。I will check the date and population covered by the statistics.
- 将来推計は、仮定によって 結果が 変わります。Projection results change with their assumptions.
- 工事は 進んでいますが、開業時期は 確定していません。Construction is progressing, but the opening date has not been fixed.