כשהיא הייתה חוזרת הביתה, היא הייתה הולכת לאט על המדרכה כי היא תמיד הייתה זהירה מאוד.

כש־ is a very common Hebrew prefix meaning when. It is attached directly to the next word, so כשהיא is literally when she.

It is a shorter everyday form of כאשר היא. In normal spoken and written Hebrew, the attached form is much more common.

הייתה + participle often describes a repeated, habitual, or ongoing action in the past.

So:

• היא חזרה הביתה = she returned home, one completed event
• היא הייתה חוזרת הביתה = she used to return home / she would return home

In this sentence, the idea is not one single return home, but a repeated pattern in the past.

Because of הייתה חוזרת, it usually has a habitual sense, so whenever she returned or when she used to return is the best fit.

If the sentence were about one specific past event, Hebrew would more naturally use כשהיא חזרה.

They all agree with the subject היא, which is feminine singular.

In Hebrew, participles and adjectives must match the gender and number of the subject.

So with היא:

• חוזרת
• הולכת
• זהירה

If the subject were masculine singular, you would get:

• חוזר
• הולך
• זהיר

Because this is a separate verb phrase, and Hebrew marks that past habitual meaning again.

The sentence has more than one past description:

• she used to return home
• she used to walk slowly
• she was always very careful

Hebrew normally repeats היה / הייתה with each of these parts instead of using it only once at the beginning.

In Hebrew, adjectives can be the main predicate of a sentence.

In the present tense, Hebrew usually does not say is:

• היא זהירה מאוד = she is very careful

But in the past, Hebrew uses היה / הייתה:

• היא הייתה זהירה מאוד = she was very careful

So הייתה here is simply the past form of to be.

That final ־ה is the directional heh, an old but still very common ending that means movement to a place.

So:

• בית = house/home
• הביתה = homeward / to home

This is why Hebrew does not need a preposition like ל־ here.

Other common examples are:

• העירה = to the city
• החוצה = outside
• פנימה = inward / inside

Here לאט functions as an adverb, meaning slowly.

Hebrew often uses simple words as adverbs without changing their form the way English often does with -ly.

So:

• היא הולכת לאט = she walks slowly

You could also say באיטיות, which is more formal, but לאט is very common and natural.

Because על means on, and a sidewalk is treated as a surface you walk on.

So:

• על המדרכה = on the sidewalk

במדרכה would sound like in the sidewalk, which is usually not what is meant.

Hebrew often uses the definite article in places where English also says the sidewalk, especially when talking about the known setting of the action.

So על המדרכה is the natural way to say on the sidewalk here.

על מדרכה without ה־ would usually sound less natural in this sentence.

Hebrew often does drop subject pronouns, but not always.

In a longer sentence like this, repeating היא helps keep the structure clear:

• כשהיא הייתה חוזרת הביתה, היא הייתה הולכת...

It marks the start of the main clause clearly and sounds natural. Leaving it out is sometimes possible in Hebrew, but this version is clearer and very normal.

Both are possible in Hebrew, but זהירה מאוד is a very common and natural order.

So:

• היא הייתה זהירה מאוד
• היא הייתה מאוד זהירה

Both can work. The version in the sentence is completely standard. The difference is mostly one of style or emphasis, not basic meaning.

כי is a very common word meaning because in sentences like this.

Hebrew also has other ways to say because, such as:

• מפני ש־
• בגלל ש־

But כי is simple, common, and natural here.

It is standard and helpful.

The first part, כשהיא הייתה חוזרת הביתה, is a subordinate time clause. When that kind of clause comes first, Hebrew often uses a comma before the main clause.

So the comma makes the sentence easier to read and follows normal written style.