What is と Conditional?
と expresses natural consequences, automatic results, and habitual actions. It means "when" or "whenever," indicating that Y naturally/automatically happens when X occurs.
春になると、桜が咲く
"When spring comes, cherry blossoms bloom" (natural)
このボタンを押すと、ドアが開く
"When you press this button, the door opens" (automatic)
彼に会うと、いつも話が長い
"When I meet him, the conversation is always long" (habitual)
Formation
Pattern: [Condition] + と + [Natural Result]
With verbs: Dictionary form + と
| Verb | + と | Example |
|---|---|---|
| 押す | 押すと | 押すと開く |
| 行く | 行くと | 行くとある |
| 食べる | 食べると | 食べると太る |
With い-adjectives: Remove い + いと
高い → 高いと
"When/if it's expensive"
寒い → 寒いと
"When it's cold"
With な-adjectives and nouns: + だと
静かだと - When it's quiet
学生だと - When (someone is) a student
雨だと - When it's rain/rainy
Basic Usage
Natural/automatic consequences
水を熱すると、沸騰する
"When you heat water, it boils"
右に曲がると、駅がある
"When you turn right, there's a station"
このスイッチを入れると、電気がつく
"When you turn on this switch, the light comes on"
Habitual actions
朝起きると、コーヒーを飲む
"When I wake up in the morning, I drink coffee"
日本に行くと、いつも寿司を食べる
"When I go to Japan, I always eat sushi"
彼に会うと、元気になる
"When I meet him, I become energetic"
General truths
春になると、暖かくなる
"When spring comes, it gets warm"
練習すると、上手になる
"When you practice, you improve"
年を取ると、忘れっぽくなる
"When you get old, you become forgetful"
Key Characteristics
Cannot use with commands/requests
Wrong: 暇だと、手伝って ❌
Right: 暇だったら、手伝って ✓
Or: 暇なら、手伝って ✓
"If you're free, help me"
と cannot be followed by commands!
Use たら or なら instead
Cannot use with volitional expressions
Wrong: 明日晴れると、行こう ❌
Right: 明日晴れたら、行こう ✓
"If it's sunny tomorrow, let's go"
Cannot use with ~よう, ~ましょう, ~たい after と
Can use with past tense results
家に帰ると、猫が寝ていた
"When I got home, the cat was sleeping"
ドアを開けると、誰もいなかった
"When I opened the door, no one was there"
Describes discovery/observation
Common Conversations
Example 1: Directions
A: 駅への行き方を教えてください
"Please tell me how to get to the station"
B: この道をまっすぐ行くと、駅があります
"When you go straight on this road, there's the station"
A: ありがとうございます
"Thank you"
Example 2: How Things Work
A: このボタンは何ですか
"What is this button?"
B: これを押すと、エアコンがつきます
"When you press this, the AC turns on"
A: なるほど
"I see"
Example 3: Habits
A: 毎朝何してる？
"What do you do every morning?"
B: 起きると、すぐシャワーを浴びるよ
"When I wake up, I take a shower right away"
Common Mistakes
Mistake 1: Using with commands
Wrong: 雨が降ると、傘を持って行って ❌
Right: 雨が降ったら、傘を持って行って ✓
"If it rains, take an umbrella"
と cannot precede commands!
Mistake 2: Using with volitional
Wrong: 安いと、買おう ❌
Right: 安かったら、買おう ✓
"If it's cheap, let's buy it"
Cannot use ~う/~よう after と
Mistake 3: Using for one-time hypothetical
Unnatural: 明日雨が降ると、中止です ⚠️
Natural: 明日雨が降ったら、中止です ✓
"If it rains tomorrow, it's cancelled"
と is better for habitual/general, use たら for specific future
と for Discoveries
Past tense discoveries
ドアを開けると、そこには美しい庭があった
"When I opened the door, there was a beautiful garden"
窓から外を見ると、雪が降っていた
"When I looked outside from the window, it was snowing"
Describes what you discovered/found
Scientific Facts
Natural laws
温度が下がると、水は凍る
"When temperature drops, water freezes"
地球が回ると、昼と夜ができる
"When the Earth rotates, day and night occur"
物を落とすと、下に落ちる
"When you drop something, it falls down"
と vs たら
と - Natural/habitual
春になると、桜が咲く
"When spring comes, cherry blossoms bloom" (every year)
Automatic, habitual, general truth
たら - Hypothetical/specific
春になったら、お花見に行こう
"When spring comes, let's go cherry blossom viewing"
Specific future plan, hypothetical
Giving Directions
Common with と
まっすぐ行くと、信号がある
"When you go straight, there's a traffic light"
その角を曲がると、郵便局が見える
"When you turn that corner, you can see the post office"
二つ目の交差点を左に曲がると、学校がある
"When you turn left at the second intersection, there's a school"
Mechanical Instructions
How things work
ここを押すと、開く
"When you press here, it opens"
このレバーを引くと、水が出る
"When you pull this lever, water comes out"
電源ボタンを長押しすると、電源が切れる
"When you press and hold the power button, it turns off"
Seasonal Changes
Natural cycles
夏になると、暑くなる
"When summer comes, it gets hot"
秋になると、葉が落ちる
"When autumn comes, leaves fall"
冬になると、雪が降る
"When winter comes, it snows"
Personal Habits
Daily routines
夜になると、眠くなる
"When night comes, I get sleepy"
お酒を飲むと、顔が赤くなる
"When I drink alcohol, my face turns red"
辛いものを食べると、汗が出る
"When I eat spicy food, I sweat"
Cause and Effect
Automatic results
頑張りすぎると、疲れる
"When you try too hard, you get tired"
運動すると、お腹が空く
"When you exercise, you get hungry"
たくさん食べると、太る
"When you eat a lot, you gain weight"
Physical Reactions
Natural responses
寒いと、震える
"When it's cold, I shiver"
怖いと、叫ぶ
"When I'm scared, I scream"
嬉しいと、笑顔になる
"When I'm happy, I smile"
Time Expressions with と
General time
12時になると、お昼休みだ
"When it becomes 12 o'clock, it's lunch break"
週末になると、人が多い
"When it becomes the weekend, there are many people"
夜になると、静かになる
"When it becomes night, it gets quiet"
と in Descriptions
Describing sequences
この道を行くと、公園があって、
その先に駅がある
"When you go down this road, there's a park,
and beyond that is the station"
Describing route or sequence
Practice Sentences
Basic
このボタンを押すと、音が鳴る
"When you press this button, a sound plays"
春になると、花が咲く
"When spring comes, flowers bloom"
まっすぐ行くと、駅がある
"When you go straight, there's a station"
Intermediate
朝早く起きると、一日が長く感じる
"When I wake up early in the morning, the day feels long"
この店に来ると、いつも同じものを注文してしまう
"When I come to this shop, I always end up ordering the same thing"
彼女に会うと、いつも元気をもらえる
"When I meet her, I always receive energy"
Advanced
経済が悪化すると、失業率が上がり、
社会全体に影響が出る
"When the economy worsens, the unemployment rate rises,
and it affects society as a whole"
このシステムを使うと、作業効率が大幅に向上し、
コスト削減にもつながる
"When you use this system, work efficiency improves significantly,
and it also leads to cost reduction"
Related Grammar Points
- たら conditional - Hypothetical/sequential
- ば conditional - General condition
- なら conditional - Contextual
- Conditionals overview - All conditional forms
- と particle - Other uses of と
- Natural consequences - Automatic results