kyou no katudou ha kuzi ni hazimarimasu.

の connects one noun to another noun. Here, 今日の活動 means today’s activity or the activity for today.

So the structure is:

• 今日 = today
• 活動 = activity
• 今日の活動 = today’s activity

This is a very common pattern in Japanese:

• 私の本 = my book
• 日本の文化 = Japanese culture
• 明日の予定 = tomorrow’s plans

は marks the topic of the sentence. The topic here is 今日の活動.

So the sentence is basically saying:

• As for today’s activity, it starts at nine o’clock.

This does not always translate naturally into English, but it is an important Japanese pattern. は tells the listener what the sentence is about.

When は is used as a particle, it is pronounced わ, not は.

So:

• 今日の活動は is pronounced きょう の かつどう わ

This is just a special rule for a few particles in Japanese spelling:

• は as a particle → わ
• へ as a particle → え
• を as a particle → usually お

Here, 今日 is read きょう.

That is the most natural reading in this sentence:

• 今日の活動 = きょう の かつどう

Be careful: 今日 can have other readings in some contexts, such as こんにち, but in everyday sentences meaning today, きょう is the normal reading.

九時 is read くじ.

Even though 九 is often read きゅう, with 時 the reading becomes く here:

• 一時 = いちじ
• 二時 = にじ
• 三時 = さんじ
• 四時 = よじ
• 五時 = ごじ
• 六時 = ろくじ
• 七時 = しちじ
• 八時 = はちじ
• 九時 = くじ

So 九時に is くじ に.

に marks a specific point in time. Since 九時 is a specific time, Japanese normally uses に.

So:

• 九時に始まります = starts at nine o’clock

This is very common with clock times:

• 七時に起きます = I wake up at seven
• 十時に寝ます = I go to bed at ten

Sometimes, yes, but with a precise time like 九時, learners should usually include に.

For example:

• 九時に始まります = standard and clear

With some broader time expressions, に is often omitted:

• 今日始まります = It starts today
• 明日行きます = I’ll go tomorrow

But with exact clock times, に is the normal choice.

始まります is the polite non-past form of 始まる.

That means it can mean:

• starts
• will start

depending on context.

Breakdown:

• dictionary form: 始まる
• polite form: 始まります

In this sentence, it is a polite statement about when the activity starts.

始まる and 始める are related but different verbs.

• 始まる = to begin, to start
  something starts on its own
• 始める = to start something
  someone starts something

In this sentence, the activity is the thing that begins, so 始まります is the natural choice.

Compare:

• 活動は九時に始まります。 = The activity starts at nine.
• 先生は授業を九時に始めます。 = The teacher starts the class at nine.

Japanese sentences usually put the main verb at the end. That is one of the biggest word-order differences from English.

So this sentence follows a very normal Japanese order:

• 今日の活動は = topic
• 九時に = time
• 始まります = verb

A rough pattern is:

• topic + time + verb

This is very natural in Japanese.

Yes, but the nuance changes.

• 今日の活動は九時に始まります
  As for today’s activity, it starts at nine.
• 今日の活動が九時に始まります
  It is today’s activity that starts at nine / today’s activity starts at nine.

は is better if you are simply talking about the topic.
が can sound more focused or identifying, depending on context.

For most basic situations, は is the most natural choice here.

Yes, but the nuance is a little different.

• 九時に始まります = starts at nine
• 九時から始まります = starts from nine / starts at nine

With 始まります, both can work.
に focuses on the exact time point.
から emphasizes the starting point.

So both are possible, but に is very straightforward for beginners.

Yes. 始まります is polite Japanese, often called the ます-form.

That makes the whole sentence appropriate for:

• teachers
• announcements
• formal conversation
• speaking politely to people you do not know well

A less formal version would be:

• 今日の活動は九時に始まる。

No. Japanese is normally written without spaces.

So this sentence would usually appear as:

今日の活動は九時に始まります。

Spaces are often added in beginner materials to make the grammar easier to see.

You can say 活動は九時に始まります, but it means the activity starts at nine, without specifically saying today’s activity.

Adding 今日の makes it more specific:

• 活動は九時に始まります。 = The activity starts at nine.
• 今日の活動は九時に始まります。 = Today’s activity starts at nine.

So 今日の tells us which activity you are talking about.

Yes. The Japanese non-past form often covers both present and future, depending on context.

So 始まります can mean:

• starts
• will start

In this sentence, if you are talking about today’s schedule, English will often use will start:

• Today’s activity will start at nine.

But the Japanese form itself stays 始まります.