Она тащила большой чемодан по лестнице, потому что лифт снова не работал.

Тащила comes from тащить, which means to drag, to haul, or to lug something with effort.

So она тащила большой чемодан suggests more than just she carried a big suitcase. It implies that the suitcase was heavy, awkward, or difficult to move. A more neutral verb like несла would simply mean was carrying.

So the choice of тащила adds a sense of strain.

In the past tense, Russian verbs agree with gender and number.

Because the subject is она, the verb must be feminine singular:

• он тащил — he was dragging
• она тащила — she was dragging
• оно тащило — it was dragging
• они тащили — they were dragging

So тащила is used because the subject is female.

Тащила is imperfective, and that fits the sentence well because it describes an ongoing process or background situation.

The sentence is telling us what she was doing when the reason is given:

• Она тащила большой чемодан по лестнице, потому что лифт снова не работал.

This sounds like a scene in progress: she was hauling the suitcase along the stairs because the elevator was out again.

A perfective verb would usually focus more on a completed result, such as successfully getting the suitcase somewhere. Here the emphasis is on the action itself, not its completion.

Большой чемодан is the direct object of the verb тащила, so it is in the accusative case.

However, with inanimate masculine singular nouns, the accusative looks exactly like the nominative:

• nominative: большой чемодан
• accusative: большой чемодан

So even though it is accusative, the form does not change.

The adjective must agree with the noun чемодан in:

• gender
• number
• case

Чемодан is:

• masculine
• singular
• accusative in this sentence

For an inanimate masculine singular noun, the accusative adjective form is the same as the nominative form, so we get:

• большой чемодан

If the noun were feminine, for example, the form would change differently.

По лестнице is in the dative case.

The preposition по often means along, on, over, or via, depending on context, and it commonly takes the dative.

Here, по лестнице means something like:

• along the stairs
• on the stairs
• by the stairs / using the stairs

In natural English, we usually translate it as up the stairs or down the stairs, depending on context.

The noun лестница becomes лестнице in the dative singular.

By itself, по лестнице does not explicitly say up or down.

Literally, it is more like along/on the staircase. In real usage, the exact direction is often understood from context.

So depending on the situation, English might translate it as:

• up the stairs
• down the stairs
• on the stairs

If Russian needs to make the direction completely clear, it can add words like:

• вверх по лестнице — up the stairs
• вниз по лестнице — down the stairs

Because потому что introduces a subordinate clause.

Russian normally separates subordinate clauses with a comma:

• Она тащила большой чемодан по лестнице, потому что лифт снова не работал.

This is very standard punctuation.

This means the elevator was not working again or the elevator wasn’t working again.

A few things are happening here:

• лифт is the subject, so it is in the nominative
• работал is masculine singular past tense, agreeing with лифт
• не работал means was not working
• снова means again

So the clause literally works as:

• elevator again not worked → the elevator wasn’t working again

Yes. In many contexts, снова and опять both mean again.

So you could say:

• лифт снова не работал
• лифт опять не работал

The difference is mostly stylistic:

• снова is often a bit more neutral
• опять is often a bit more conversational and can sometimes sound more emotional or slightly annoyed

Since a broken elevator is annoying, опять would sound very natural too.

Because не работал focuses on the state: the elevator wasn’t working.

• лифт не работал = the elevator was out of order / wasn’t functioning
• лифт сломался = the elevator broke

Those are related, but not identical.

In this sentence, the speaker is giving the reason she had to use the stairs. The important point is the elevator’s condition at that time, so не работал is a very natural choice.

Russian can sometimes omit subject pronouns, but in the past tense the verb does not show person clearly the way present-tense forms do.

For example, тащила tells you:

• feminine
• singular
• past

But it does not tell you whether it means I, you, or she without context.

So она is useful here because it clearly identifies the subject as she.

Russian has no articles like a or the.

So nouns like чемодан, лестница, and лифт appear without articles, and definiteness is understood from context.

For example:

• большой чемодан could mean a big suitcase or the big suitcase
• лифт could mean an elevator or the elevator

In this sentence, context makes it natural in English to say the elevator and probably a big suitcase or the big suitcase, depending on the situation.