N4 · Linking clauses
When: とき and the tense inside it
とき (when)
とき is a noun meaning "time"; the tense in front of it says before or after, not past or present.
とき is a noun meaning "time", and "when…" is built by putting a clause in front of it, exactly like any other noun: 子供のとき (when I was a child), 暇なとき (when I have time), 寒いとき (when it is cold), 日本に行くとき (when I go to Japan). Nouns take の and na-adjectives take な, as they do before any noun.
The important part is the tense of a verb in front of とき. It does not say whether something is past or present — the end of the sentence does that. It says whether the action in the clause has happened yet at the moment of the main action. Dictionary form: not yet. た-form: already.
So 日本に行くとき、カメラを買いました means the camera was bought before the journey, perhaps at home or at the airport; 日本に行ったとき、カメラを買いました means it was bought in Japan, after arriving. English says "when I went to Japan" for both and leaves the listener to guess.
A state — an adjective, いる, ある, or a verb in ている — simply describes what was true at that moment and normally stays in the present form. The subject inside the clause takes が; は after とき (ときは) sets the whole time as a topic, often in contrast with other times.
The form
| when I was a child (noun) | 子供のとき |
| when I have free time (na-adjective) | 暇なとき |
| when it is cold (i-adjective) | 寒いとき |
| when I am not busy (negative) | 忙しくないとき |
| when I go — before arriving | 行くとき |
| when I went — after arriving | 行ったとき |
| while I was walking (state) | 歩いているとき |
The rules one by one
Nouns take の, na-adjectives take な, and verbs and i-adjectives stand in the plain form before とき.
学生のとき、よくこの店に来ました。When I was a student, I often came to this shop.
Dictionary form: the action in the とき clause has not happened yet when the main action happens.
寝るとき、電気を消します。I turn off the light when I go to bed.
た-form: the action in the とき clause has already happened.
駅に着いたとき、電車はもう出ていました。When I got to the station, the train had already left.
The end of the sentence says past or future; the とき clause only says before or after.
来年日本に行ったとき、友達に会います。When I go to Japan next year, I will meet a friend.
A closer look
とき is a noun, and that explains everything
Every rule here is the rule for a clause in front of a noun. 子供のとき has の for the same reason as 子供の本, and 暇なとき has な for the same reason as 暇な人. Even the tense works as it does in any such clause: relative to the main verb, not to now.
Because it is a noun, とき can also take particles. ときに pins the action to that moment; ときは makes the time the topic, often to set it against other times: 忙しいときは、昼ご飯を食べません, "when I am busy (unlike other days), I skip lunch".
Exceptions and special cases (1)
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the clause describes a state — an adjective, いる, ある, or ている
the present form is normal even when the whole sentence is about the past.
若いとき、よく山に登りました。When I was young, I often went climbing in the mountains.
A state has no before or after: it was simply true at that moment. The past form is possible too, but it adds nothing that the end of the sentence does not already say.
How to spot it
- 〜とき、
- 〜たとき
- 〜のとき
- 〜なとき
- 〜ているとき
- 〜ときは
Example sentences
子供のとき、犬を飼っていました。When I was a child, we had a dog.
暇なとき、何をしますか。What do you do when you have free time?
家を出るとき、雨が降り始めました。Just as I was leaving the house, it started to rain.
道が分からないとき、地図を見ます。When I don't know the way, I look at a map.
京都に行ったとき、古いお寺をたくさん見ました。When I went to Kyoto, I saw a lot of old temples.
歩いているとき、昔の友達に会いました。While I was walking, I ran into an old friend.
7 more example sentences
朝起きたとき、まず水を一杯飲みます。When I get up in the morning, the first thing I do is drink a glass of water.
困ったとき、いつでも電話してください。Whenever you are in trouble, please call me.
日本に来たとき、日本語が全然話せませんでした。When I came to Japan, I couldn't speak any Japanese.
出かけるとき、鍵を忘れないでください。Don't forget your keys when you go out.
天気がいいときは、自転車で会社に行きます。When the weather is good, I cycle to work.
祖父が元気だったとき、よく一緒に釣りをしました。When my grandfather was well, we often went fishing together.
電話が鳴ったとき、私はお風呂に入っていました。When the phone rang, I was in the bath.
Worth knowing (1)
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Usually written in kana
As a grammatical noun, "when" is normally written とき. The kanji 時 is not wrong, and you will see it, but many writers keep it for the noun "time" in a fuller sense and write the grammar in kana — the same habit as with こと and もの.
時が経つのは早いですね。Time really flies, doesn't it?
The trap English speakers fall into
Watch out
ただいま is said on arrival, after the coming home has happened, so the clause needs the た-form even though this is a present-tense habit. 帰るとき would mean "as I set off for home" — when you say goodbye at work, not when you open your own front door.
In front of とき, the dictionary form means not yet and the た-form means already.
Your turn
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