～と (to) - automatic conditional

This grammar connects two parts of a sentence. The first part is the condition. The second part is the result. The particle と acts as the bridge. It translates roughly to "whenever" or "if... then." However, it is much stricter than the English word "if." In English, you might say "If I feel like it, I will go." You cannot do that with ～と. It only works for things that are guaranteed. Think of it as a "cause and effect" machine. You provide the input, and the machine provides the output. It describes a world where things are predictable. This makes it perfect for describing nature or math. It also works for personal habits that never change. If you drink coffee and always get a headache, use ～と.

1. 1Building this rule is actually quite simple. You mostly use the dictionary form of words.
2. 2For Verbs, use the Dictionary Form (Present Affirmative) or the Nai-form (Present Negative). Just add と directly. Example: 飲む (drink) becomes 飲むと (whenever I drink).
3. 3For I-Adjectives, keep the い at the end and add と. Example: 寒い (cold) becomes 寒いと (whenever it is cold).
4. 4For Na-Adjectives, you must add だ before the と. Example: 静か (quiet) becomes 静かだと (whenever it is quiet).
5. 5For Nouns, it works just like Na-Adjectives. Add だ before the と. Example: 冬 (winter) becomes 冬だと (whenever it is winter).
6. 6Remember, you never use the past tense before と. The condition is always in the present tense because it is a general rule.

There are four main scenarios where ～と shines. First, use it for Natural Phenomena. When the sun sets, it gets dark. When spring comes, flowers bloom. These are facts of nature. Second, use it for Machine Operations. If you turn this key, the engine starts. If you push this lever, the seat reclines. It is the language of instruction manuals. Third, use it for Giving Directions. Go straight and you will see the bank. Turn left and the station is right there. The station does not move, so the result is "automatic" for anyone following the path. Finally, use it for Constant Habits. Whenever I see a cat, I smile. It is my personal rule of life. Yes, even native speakers find this habit relatable. It shows a predictable pattern in your behavior.

This is the most important part to remember. You cannot use ～と if the second part of the sentence involves your will. This means no requests, no invitations, and no personal plans. You cannot say "If it is sunny, let's go to the park" using ～と. Why? Because going to the park is a choice, not a law of physics. Avoid using words like ～てください (please do), ～ましょう (let's), or ～たい (I want to) after と. If the result depends on someone's decision, ～と is the wrong tool. It would sound like you are a robot trying to force someone to act. Use ～たら instead for those situations. Keep ～と for things that happen whether you want them to or not.

Many learners forget the だ for Nouns and Na-Adjectives. Saying 学生と means "with a student." Saying 学生だと means "if one is a student." That small だ changes everything. Another mistake is using the past tense in the first clause. You might want to say "If I went," but ～と does not work that way. Always stay in the dictionary form. Also, watch out for "one-time" events. If you are talking about a specific thing you will do tomorrow, do not use ～と. It is for things that happen "whenever." If you use it for a one-time plan, people might think you are a programmed machine. You are a human, so show your flexibility with other conditionals!

Japanese has many ways to say "if." The most common is ～たら. Think of ～たら as the "General If." It can do almost anything. It handles personal plans and one-time events easily. Then there is ～ば. This is the "Logical Condition." It focuses on the requirement needed for a result. If you compare them, ～と is the most restrictive. It is the "Automatic If." While ～たら is like a conversation, ～と is like a science textbook. If you use ～と, you are emphasizing that the result is 100% certain. If there is even a 1% chance the result might not happen, ～たら is usually safer.