watasi ha yoru ni mizu wo nomimasen.

I do not drink water at night.

Breakdown of watasi ha yoru ni mizu wo nomimasen.

• は: topic particle
• 私わたし: I
• を: direct object particle
• 水みず: water
• 飲のむ: to drink
• に: time particle
• 夜よる: night
• 〜ません: negative polite form

Questions & Answers about watasi ha yoru ni mizu wo nomimasen.

Why is は used after 私 instead of が?

は is the topic marker. It tells the listener “I’m talking about me.” In this sentence, 私 (I) is the topic.

• が would mark the grammatical subject and is often used to introduce new information.
• Since 私 is known or given from context (“As for me…”), は is the correct choice.

Why do we put に after 夜?

The particle に marks a specific point in time when an action happens.

• 夜に means “at night.”
• Without に, 夜 can sound more like a general time-frame (often used with は, as in 夜は).

Can we drop に and just say 夜?

Yes, in casual speech learners sometimes omit に, but it changes the nuance:

• 夜に水を飲みません。 emphasizes the time “at night.”
• 夜水を飲みません。 is colloquial; it’s understood but less precise.
• If you use 夜は instead, you contrast “night” with other times: “As for at night, I don’t drink water.”

What is the word order in this sentence? Why does 水を come before 飲みません?

Japanese follows Subject-Time-Object-Verb (S-T-O-V) order:

1. 私（Subject）
2. 夜に（Time）
3. 水を（Object）
4. 飲みません（Verb）
   The verb always goes at the end, so 飲みません comes last.

Why is を used after 水?

The particle を marks the direct object of the verb.

• 水を飲む literally is “drink water.”
• 水を飲みません is “do not drink water.”

How do you form the negative polite verb 飲みません?

For ‐ます verbs (Type 1), drop ます and add ません:

1. Dictionary form: 飲む
2. Polite positive: 飲みます
3. Polite negative: 飲みません

What’s the difference between 飲みません and 飲まない?

• 飲みません is polite/formal.
• 飲まない is plain/informal.
  Use 飲みません with strangers, in class, or in polite company.

Why is 私 (I) explicitly stated? Can we omit it?

Japanese often drops subjects when they’re clear from context.

• If it’s obvious you’re talking about yourself, you can simply say 夜に水を飲みません。
• You include 私 when you want to emphasize or clarify “I.”

Does this sentence mean “I will not drink water tonight” or “I don’t drink water at night”?

Japanese present tense covers both habitual actions and near-future events.

• 夜に水を飲みません。 can mean:
  • Habitual: “I don’t drink water at night (ever).”
  • Future: “I’m not going to drink water tonight.”
  Context and additional time words (e.g., 今夜 for “tonight”) clarify which you mean.