N4 · Conditions
Conditional と: whenever
the conditional と
A, と, B: whenever A happens, B follows by itself.
Put と after the plain non-past form of a verb or adjective, and the sentence says that the second half follows the first automatically: 春になると、桜が咲きます, "when spring comes, the cherry trees bloom". Nobody decides it; it is how things work. That makes と the conditional of natural laws, machines, habits and directions.
The form before と is plain, even in a polite sentence: the politeness is carried by the end of the sentence, 咲きます, not by the middle. (Very formal announcements sometimes say 〜ますと; you will hear it, but you do not need to produce it.) An i-adjective takes と directly (寒いと); a na-adjective or a noun needs だ in front of it (雨だと).
Because the result is automatic, the second half cannot be something the speaker still wants to bring about: no request, no invitation, no wish, no plan. "When you get to the station, call me" is a request, so it takes たら, not と. This is the mistake English speakers make most often with と, because "when" and "if" in English carry no such restriction.
With a past-tense ending, と tells a story: you did one thing and found something, or one event followed another. 窓を開けると、雪が降っていました is "when I opened the window, it was snowing" — a discovery, not a rule.
The form
| verb, plain non-past | 押すと |
| verb, plain negative | 押さないと |
| i-adjective | 寒いと |
| na-adjective + だ | 静かだと |
| noun + だ | 雨だと |
The rules one by one
The form this topic is about
と follows the plain non-past form, even when the sentence ends in です or ます.
このボタンを押すと、水が出ます。Press this button and water comes out.
The second half happens by itself; it is a result, not a decision.
春になると、暖かくなります。When spring comes, it gets warm.
No request, invitation, wish or plan may follow と; use たら for those.
駅に着いたら、電話してください。When you get to the station, please call me.
With a past-tense ending, と reports what you found or what happened next.
窓を開けると、雪が降っていました。When I opened the window, it was snowing.
Directions use と: go this way and you will come to it.
この道をまっすぐ行くと、右に銀行があります。Go straight along this road and there is a bank on the right.
A closer look
と in a story
In narrative, と with a past-tense ending links two events in the order they happened, and the second one is usually something the narrator could not control: 外に出ると、雨が降り始めていました, "when I went out, it had started to rain". The first half is an action, the second is what the world did.
This is why と is common in novels and in retold experiences. Written narrative also uses it for one person's actions in quick succession — 彼は部屋に入ると、窓を開けた, "he came into the room and opened the window" — but in conversation, a sequence of your own choices such as "I came home and then I cooked" is said with the te-form: 家に帰って、料理をしました.
Exceptions and special cases (1)
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the second half is いい or いいですね
と expresses a hope, "it would be nice if", even though a hope looks like a wish.
明日、晴れるといいですね。I hope it is fine tomorrow.
Grammatically the second half is a judgement — "it is good" — not a request, so the rule is not broken. In use, 〜といいですね is one of the most common ways to wish somebody well.
How to spot it
- 〜と、
- 押すと
- 〜になると
- 〜だと
- 〜ないと
Example sentences
水は百度になると、沸騰します。Water boils when it reaches a hundred degrees.
この道をまっすぐ行くと、右に郵便局があります。If you go straight along this road, the post office is on the right.
私はコーヒーを飲むと、眠れなくなります。When I drink coffee, I cannot sleep.
お金を入れてボタンを押すと、切符が出てきます。Put the money in and press the button, and the ticket comes out.
冬になると、この湖は凍ります。In winter this lake freezes.
部屋に入ると、電気がついていました。When I went into the room, the light was on.
7 more example sentences
右に曲がると、公園が見えます。Turn right and you will see a park.
寝る前にスマホを見ると、よく眠れません。If I look at my phone before bed, I do not sleep well.
暗くなると、街灯が自動でつきます。When it gets dark, the street lights come on automatically.
このアプリを開くと、今日の天気が分かります。Open this app and you can see today's weather.
弟は疲れると、すぐ機嫌が悪くなります。When my younger brother gets tired, he soon gets grumpy.
外に出ると、雨が降り始めていました。When I went outside, it had started to rain.
値段が高いと、誰も買いません。If the price is high, nobody buys it.
Worth knowing (2)
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ないと on its own: I have to
In conversation a sentence can stop after 〜ないと: もう行かないと, literally "if I do not go now…". The missing end is "it will be bad", and the whole thing means "I have to go". It is the short form of 〜ないといけない.
すみません、もう帰らないと。Sorry, I really have to get home.
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Habits in the past
With a past-tense ending and a time like 子どものころ, と describes something that happened every time: "whenever summer came, we swam". It is the past of the automatic rule, not a single discovery.
子どものころ、夏になると毎日海で泳ぎました。As a child, whenever summer came, I swam in the sea every day.
The trap English speakers fall into
Watch out
English says "when you arrive, call me" without a second thought, so と looks like the obvious translation of "when". But と only allows a second half that follows automatically, and a request is a choice somebody has to make. Requests, invitations, wishes and plans take たら.
と is for what always follows: press it and it happens.
Your turn
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