Learn Hardcore Japanese: sensei ha syuumatu ni yasumimasu.

は is the topic‐marker. It sets 先生 as the topic of the sentence, so you’re literally saying “As for the teacher, (he/she) rests on the weekend.” It doesn’t mark the grammatical subject (that’s が), but highlights 先生 as what the sentence is about.

Why is に used after 週末?

に is the particle that marks a specific point in time. When you say 週末に, it means “at/on the weekend.” It tells you when the teacher rests.

Can I drop に after 週末?

Generally, you need に with time expressions like 週末 to be grammatically correct.
• In casual conversation, some speakers might omit it (e.g. “週末休みます”), but in formal writing or clear speech, you should include に.

What verb form is 休みます, and what does it mean?

休みます is the polite non-past form of 休む (to rest; to take a day off).
• Polite form (–ます) is used in formal situations.
• Non-past covers both present and future: “rests,” “will rest,” or even “rests regularly,” depending on context.

Does 休みます refer to a one-time action or a habitual action?

It can be either:
• One-time: “The teacher will rest this weekend.” (often made clear by context or words like 今週末)
• Habitual: “The teacher rests on weekends (every weekend).” (you’d add いつも or 毎週末 to emphasize habit)

How do you turn this sentence into a question?

Change the ending ます to ますか:
先生は週末に休みますか。
This asks “Does the teacher rest on the weekend?”

How do you make it negative?

Replace ます with ません:
先生は週末に休みません。
This means “The teacher does not rest on the weekend.”

What’s the difference between 先生は週末に休みます and 先生が週末に休みます?

• は (topic marker): States a general fact about the teacher.
• が (subject marker): Emphasises 先生 as the one doing the action, often used to introduce or single out the teacher among others.
In neutral statements of routine, は is more common; が might occur if you’re contrasting or specifying "it’s the teacher (not someone else) who rests."