Probability and Questions: だろう, でしょう, どうして, and なに

When learning Japanese, it's essential to grasp the basic grammar points to build a strong foundation. This post will cover four key concepts: だろう, でしょう, どうして, and なに. We'll keep things simple and easy to understand, focusing on the JLPT N5 level.

だろう and でしょう

Both だろう and でしょう are used to express probability or conjecture. They can be translated as "probably" or "I think" in English. The primary difference lies in their formality and usage context.

ExpressionUsageExample SentenceTranslation
だろうInformalあめ が ふる だろう。It will probably rain.
でしょうFormalあめ が ふる でしょう。It will probably rain.
  • だろう is typically used in casual conversations among friends or people of the same social status.
  • でしょう is used in more formal situations or when speaking to someone of higher status.

In addition to expressing probability, だろう and でしょう can also be used to form questions. This usage often seeks confirmation or agreement from the listener. When used in this context, they function similarly to "right?" or "don't you think?" in English. Here's how each is used:

ExpressionUsageExample SentenceTranslation
だろうInformalこれ は やすい だろう?This is cheap, right?
でしょうFormalこれは やすい でしょう?This is cheap, don't you think?
  • だろう as a question: Used in informal settings, it seeks the listener's agreement or confirmation in a casual manner.

かれ は げんき だろう? - He is well, right?

これ は おいしい だろう? - This is delicious, right?

  • でしょう as a question: Used in more formal contexts, it also seeks agreement but in a polite and respectful way.

かのじょ は げんき でしょう? - She is well, don't you think?

きょう は あつい でしょう? - It's hot today, don't you think?

どうして

どうして is a question word that means "why" or "how come." It is used to ask for reasons or explanations.

UsageExample SentenceTranslation
Asking "why"どうして べんきょう しない の?Why don't you study?
Asking "how come"どうして ここ に いる の?How come you are here?
  • どうして is straightforward and used to seek reasons or causes behind actions or situations.

なに

なに means "what" and is used to ask about things or actions. It can be used in various contexts to inquire about different subjects.

UsageExample SentenceTranslation
Asking about objectsなに が すき です か?What do you like?
Asking about actionsなに を しています か?What are you doing?
Asking for clarificationこれは なに です か?What is this?
  • なに is versatile and essential for asking questions about unknown things or actions.

Example Sentences in Context

  • だろう/でしょう

かれ は いえ に いる だろう。 - He is probably at home.

かのじょ は すぐ くる でしょう。 - She will probably come soon.

  • どうして

どうして きょう は やすんだ の? - Why did you take a break today?

  • なに

なに が ひつよう です か? - What do you need?

それ は なに を いみ して います か? - What does that mean?

Understanding these basic grammar points—だろう, でしょう, どうして, and なに—is crucial for beginners learning Japanese. They help in forming questions, expressing probability, and seeking explanations, all fundamental for everyday conversation.