לפני ההמראה אני תמיד חוגרת חגורת בטיחות ואז שותה מים.

Because the speaker is female.

In Hebrew present tense, verbs usually agree with the subject’s gender and number.
So:

• אני חוגרת = I fasten / I am fastening said by a woman
• אני חוגר = I fasten / I am fastening said by a man

So this sentence is spoken by a female speaker.

Because with this verb, the masculine singular and feminine singular forms are the same in the present tense.

So both a man and a woman can say:

• אני שותה מים = I drink water

That is different from verbs like לחגור, where the forms are different:

• חוגר = masculine singular
• חוגרת = feminine singular

So in this sentence, חוגרת shows that the speaker is female, but שותה does not.

Here לפני means before in a time sense.

So:

• לפני ההמראה = before takeoff

Be aware that לפני can also mean in front of, depending on context.
For example:

• לפני הבית = in front of the house

So לפני can be either temporal (before) or spatial (in front of).

המראה means takeoff.

It comes from the verb להמריא, which means to take off or to soar.

The ה־ at the beginning is the definite article, meaning the.

So:

• המראה = takeoff
• ההמראה = the takeoff

In English we often just say before takeoff, but in Hebrew it is very natural to say לפני ההמראה.

Because this is a construct phrase in Hebrew.

In Hebrew, when one noun modifies another noun, the first noun often changes form. This is called smikhut or the construct state.

Here:

• חגורה = belt
• בטיחות = safety
• חגורת בטיחות = safety belt / seat belt

So חגורת is the construct form of חגורה.

This pattern is very common in Hebrew, for example:

• בית ספר = school literally house of book
• בקבוק מים = water bottle
• חגורת בטיחות = safety belt

Because את is only used before a definite direct object.

Here, חגורת בטיחות is indefinite, meaning a seat belt or seat belt in a general sense. So there is no את.

• אני חוגרת חגורת בטיחות = I fasten a seat belt / I fasten my seat belt in a general statement

If it were definite, you would use את:

• אני חוגרת את חגורת הבטיחות = I fasten the seat belt

So the absence of את tells you the object is not grammatically definite.

Because Hebrew often leaves out a repeated subject when it is already understood.

So:

• אני תמיד חוגרת חגורת בטיחות ואז שותה מים

means:

• I always fasten a seat belt and then drink water

The subject אני applies to both verbs. Repeating it would also be possible, but it would sound more explicit or emphatic:

• אני תמיד חוגרת חגורת בטיחות ואז אני שותה מים

That is grammatical, but less natural in a simple sentence like this.

ואז means and then or simply then.

It is made of:

• ו־ = and
• אז = then

So it connects the two actions in sequence:

1. חוגרת חגורת בטיחות
2. ואז שותה מים

In other words: first one action happens, then the next.

That is a normal Hebrew word order.

• אני תמיד חוגרת... = I always fasten...

Hebrew word order is somewhat flexible, but this is a very natural neutral order:

• subject + adverb + verb

So:

• אני תמיד חוגרת = I always fasten

You might also see other orders for emphasis, but this one is standard and common.

In Hebrew, the present tense often covers both meanings.

So חוגרת and שותה can mean:

• I fasten / I am fastening
• I drink / I am drinking

In this sentence, because of תמיד (always) and the overall meaning, it clearly describes a habitual action:

• Before takeoff, I always fasten a seat belt and then drink water.

So here the best understanding is the simple present: a routine or habit.

Yes. מים means water, even though it looks like a plural form.

This is one of several Hebrew nouns that are plural in form but often refer to a substance or mass rather than separate countable items.

So:

• מים = water

You simply learn it as the normal Hebrew word for water.
Even though it looks plural, in English you translate it as singular water.

לחגור means to fasten, to buckle, or sometimes to put on something like a belt or safety device.

In this sentence:

• חוגרת חגורת בטיחות = fastens / buckles a seat belt

It is the natural verb for seat belts.

Related usage:

• לחגור חגורה = to put on / fasten a belt
• לחגור חגורת בטיחות = to fasten a seat belt

So this is more specific than just a general verb like to do or to put.

Yes, but one word would change.

A male speaker would say:

• לפני ההמראה אני תמיד חוגר חגורת בטיחות ואז שותה מים.

The only change is:

• חוגרת → חוגר

Everything else can stay the same, including שותה, because that form does not change between masculine singular and feminine singular in the present tense for this verb.