mezamasidokei ga naru mae ni me ga samemasita.

Because the sentence contains two separate clauses, and each clause has its own subject.

• 目覚まし時計が鳴る

  • 目覚まし時計 = alarm clock
  • が marks it as the subject
  • 鳴る = to ring

• 目が覚めました

  • 目 is part of the expression 目が覚める
  • が marks the subject inside that expression
  • 覚めました = woke up / became awake

So this is not one subject being marked twice. It is really:

• Before the alarm clock rang,
• my eyes woke / I woke up.

Japanese often allows multiple が in one sentence when there are multiple clauses.

Before 前に, Japanese normally uses the dictionary form of the verb when the action has not happened yet at that point.

So:

• 鳴る前に = before it rings
• 食べる前に = before eating
• 寝る前に = before sleeping

Using 鳴った前に would sound unnatural here.

A useful rule of thumb:

• Verb dictionary form + 前に = before doing X
• Noun + の + 前に = before X

Examples:

• 家を出る前に = before leaving the house
• 授業の前に = before class

Because 鳴る前に means before it rang / before it would ring from the viewpoint of that past event.

In Japanese, with 前に, the verb stays in the dictionary form even if the whole sentence is talking about the past.

So:

• 目覚まし時計が鳴る前に目が覚めました。 = I woke up before the alarm clock rang.

The main action that actually happened and completes the sentence is 覚めました, so that is where the past marking appears.

Here, 前に means before.

It connects the first action to the second:

• 目覚まし時計が鳴る前に = before the alarm clock rings
• 目が覚めました = I woke up

So the sequence is:

1. I woke up
2. The alarm had not rung yet

In other words, 前に sets a time point earlier than the event in the first clause.

目が覚める literally means something like the eyes open / the eyes become awake, but as a set expression it means:

• to wake up
• to awaken

This is an idiomatic Japanese expression. Even though 目 literally means eye, the whole phrase should be learned together as 目が覚める.

So in practice:

• 朝早く目が覚めた。 = I woke up early in the morning.

It does not usually mean only that your eyes physically opened. It often means your state changed from sleeping to awake.

Both can be translated as to wake up, but they are not exactly the same.

• 目が覚める

  • focuses on becoming awake
  • the moment sleep ends
  • often natural or spontaneous

• 起きる

  • can mean to get up
  • often focuses more on physically getting out of bed or being up

For example:

• 6時に目が覚めた。 = I woke up at 6.
• 6時に起きた。 = I got up at 6.

Sometimes they overlap, but in this sentence 目が覚めました emphasizes that the speaker became awake before the alarm rang.

Because 鳴る is an intransitive verb, meaning to ring on its own.

• 目覚まし時計が鳴る = the alarm clock rings

By contrast, 鳴らす is transitive, meaning to ring something / make something ring.

• ベルを鳴らす = ring the bell
• アラームを鳴らす = set off / make the alarm ring

In this sentence, the alarm clock itself is the thing doing the ringing, so 鳴る is the natural choice.

Because 覚める is an intransitive verb. It describes a state change that happens, not an action done directly to an object.

So:

• 目が覚める = to wake up

The が marks what undergoes the change.

If you use を, that would suggest a direct object, but 覚める does not take one in this expression.

There is also a related transitive pattern:

• 目を覚ます = to wake up / to awaken oneself / to wake someone up, depending on context

Compare:

• 目が覚めた。 = I woke up.
• 目を覚ました。 = I woke up / I opened my eyes / I came to my senses.

Both exist, but 目が覚める is a very common fixed expression.

Because 目覚まし時計 is a single compound noun meaning alarm clock.

It is made from:

• 目覚まし = waking up / wake-up
• 時計 = clock

Together they form one word:

• 目覚まし時計 = alarm clock

So you do not say 目覚ましの時計 here unless you mean something more unusual or descriptive. The standard word is simply 目覚まし時計.

Yes. In normal Japanese writing, it would usually be written without spaces:

目覚まし時計が鳴る前に目が覚めました。

The spaced version is often used only for learners, to make the structure easier to see.

覚めました is the polite past form of 覚める.

So the sentence is polite but neutral in tone.

Compare:

• 目が覚めました。 = polite
• 目が覚めた。 = plain / casual

If you were talking casually to a friend, you might say:

目覚まし時計が鳴る前に目が覚めた。

The meaning stays the same; only the politeness level changes.