ドアを開ける

You use the object ドア (doa) followed by the particle を (o). Then you add the verb 開ける (akeru). In casual speech, you can just say ドア開ける. For polite situations, use ドアを開けます. It is a simple subject-object-verb structure. Just remember that 開ける is an action you perform.

Use it when you arrive at a friend's apartment. Use it when you are getting into a taxi. It is perfect for asking someone for a favor. "Can you open the door?" is a very common request. You will hear this at home, work, and shops. It is a truly universal phrase.

Do not use this for opening a book or a bottle. While 開ける works for bottles, ドア is specific to doors. Also, do not use it for "opening" a computer program. For software, Japanese people usually say "start" or "launch." Avoid using it for metaphorical "opening of hearts" unless being poetic. Stick to physical doors for now.

Japan has a mix of Western doors and sliding doors. Sliding doors are called 引き戸 (hikido). Even so, ドア is the most common word for any door. In Japan, automatic doors are everywhere, especially in convenience stores. You might see the door open without anyone touching it! Always knock before you ドアを開ける to show good manners.

If a door opens by itself, use ドアが開く (doa ga aku). If you want someone to open it, say 開けて (akete). For a very formal request, try 開けていただけますか. You can also replace ドア with 窓 (mado) for windows. These small changes help you fit into any situation.