asa sitizi ni mezamasi ga natta node, sugu okimasita.

Yes. 朝七時に means at seven in the morning, or simply at 7 a.m.

• 朝 = morning
• 七時 = seven o’clock
• に = at

Japanese often puts time expressions together like this:

• 朝七時に = at 7 in the morning
• 夜十時に = at 10 at night

You could also just say 七時に if the morning part is obvious from context, but 朝 makes it explicit.

Here, に marks a specific point in time.

So:

• 七時に = at seven o’clock

Japanese often uses に with exact times:

• 三時に = at 3:00
• 月曜日に = on Monday
• 六月一日に = on June 1st

But it is not used with every time word. For example:

• 今日 = today
• 明日 = tomorrow
• 毎朝 = every morning

Those usually do not take に.

Yes. 目覚まし here means alarm clock or alarm, and it is often short for 目覚まし時計.

• 目覚まし時計 = alarm clock
• 目覚まし = alarm / alarm clock

In everyday speech, shortening it to 目覚まし is very common.

In this sentence, it means the thing that woke the speaker up by ringing.

Because 鳴る is an intransitive verb. It means to ring or to sound by itself.

So:

• 目覚ましが鳴った = the alarm rang

The alarm is the subject, so it takes が.

Compare:

• 鳴る = something rings
• 鳴らす = to make something ring

For example:

• ベルが鳴る = the bell rings
• ベルを鳴らす = ring the bell

In your sentence, the alarm is not something the speaker actively rang; it simply went off, so が鳴った is correct.

Good question. 鳴った is the plain past form, while 鳴りました is the polite past form.

• 鳴った = rang
• 鳴りました = rang (polite)

In this sentence, 鳴った appears before ので, and the sentence ends with 起きました, which is polite.

This kind of mixing is very common:

• subordinate clause: plain form
• main sentence ending: polite form

So:

• 目覚ましが鳴ったので、すぐ起きました。 is completely natural.

Using 鳴りましたので、すぐ起きました is also possible, but it sounds more formal or stiff in ordinary conversation.

ので means because, since, or so. It connects a reason to a result.

So:

• 目覚ましが鳴ったので、すぐ起きました。 = Because the alarm rang, I got up right away.

The pattern is:

• plain form + ので
• na-adjective / noun + なので

Examples:

• 雨が降ったので、行きませんでした。
  • Because it rained, I didn’t go.
• 静かなので、ここで勉強します。
  • Because it’s quiet, I study here.

In your sentence, the reason is the alarm rang, and the result is I got up immediately.

Both can mean because, but the nuance is a little different.

• ので sounds a bit more neutral, explanatory, or gentle
• から can sound more direct or more like the speaker’s personal reasoning

So:

• 目覚ましが鳴ったので、すぐ起きました。
  • slightly softer, explanatory
• 目覚ましが鳴ったから、すぐ起きました。
  • also correct, a bit more direct

In many everyday situations, both work. For learners, it is useful to remember that ので often feels a little more formal or less assertive than から.

すぐ means immediately, right away, or soon, and it usually comes before the verb it modifies.

So:

• すぐ起きました = got up right away

This is a very normal position for adverbs in Japanese.

Other examples:

• すぐ行きます = I’ll go right away
• すぐ食べた = I ate immediately

Japanese adverbs often come before the verb phrase they describe.

Because the sentence is describing a completed event in the past:

1. the alarm rang
2. the speaker got up

So both actions are in the past:

• 鳴った = rang
• 起きました = got up

Even if the English translation might sometimes sound like a habitual statement in another context, this Japanese sentence is talking about one past occurrence.

Japanese very often leaves out subjects when they are understood from context.

In this sentence:

• 目覚ましが is explicitly stated as the subject of 鳴った
• but the subject of 起きました is omitted

The listener naturally understands that it means:

• I got up right away

Japanese omits I, you, he, she, etc. much more often than English does.

A more explicit version would be:

• 私は、朝七時に目覚ましが鳴ったので、すぐ起きました。

But in ordinary Japanese, the 私は is usually unnecessary unless you want contrast or emphasis.

Yes. That would make the whole sentence plain/casual:

• 朝七時に目覚ましが鳴ったので、すぐ起きた。

That sounds natural in casual speech or informal writing.

The version with 起きました is polite:

• 朝七時に目覚ましが鳴ったので、すぐ起きました。

So the difference is mainly speech level, not core meaning.

In this sentence, 朝七時に is very natural.

• 朝七時に = at 7 in the morning

You may also see 朝の七時に, but it sounds a little more explicitly like the seven o’clock of the morning. It is not wrong, but 朝七時に is often the more straightforward way to say 7 a.m.

So for everyday use, 朝七時に is a great pattern to remember.

The comma separates the reason clause from the main action:

• 目覚ましが鳴ったので、
• すぐ起きました。

It helps readability and makes the pause clear.

In Japanese, commas are often a matter of style, so you may sometimes see the sentence without one:

• 朝七時に目覚ましが鳴ったのですぐ起きました。

But with ので, using a comma is very common and easy to read.

No. Normally Japanese is written without spaces:

• 朝七時に目覚ましが鳴ったので、すぐ起きました。

The spaces are usually added in teaching materials to make it easier for learners to see the parts of the sentence.

So the natural written form is the no-space version above.