صديقتي تنزل الدرج في الصباح لأنها لا تحب المصعد.

صديقتي is made of:

• صديقة = a female friend
• ـي = my

When the possessive suffix ـي is added, the ة at the end of صديقة is pronounced as t, so:

• صديقة → صديقتي
• pronounced roughly ṣadīqatī

So صديقتي literally means my female friend.

Because the subject, صديقتي, is feminine singular.

In the imperfect tense in MSA:

• يـ is commonly used for he
• تـ is commonly used for she

So:

• ينزل = he goes down / descends
• تنزل = she goes down / descends

Since صديقتي is feminine, تنزل is the correct form.

In MSA, the imperfect verb can express several related ideas, including:

• present: she is going down
• habitual/repeated action: she goes down
• sometimes near future, depending on context

Here, because of في الصباح (in the morning), the sentence is most naturally understood as a habitual action:

• My friend goes down the stairs in the morning

So it is not just a one-time action happening right now.

Because the verb نزل already contains the idea of going down / descending.

So Arabic does not need a separate word equivalent to English down here. The phrase:

• تنزل الدرج

literally means something like:

• she descends the stairs
• or more naturally, she goes down the stairs

This is a very normal Arabic structure.

الدرج means the stairs or the staircase.

A learner may expect a plural, but Arabic often uses الدرج as a collective or general noun for a flight of stairs/staircase. So in context, it is perfectly natural to translate it as:

• the stairs

Another word you may also see is السلالم, which can also mean the stairs.

It is definite because the speaker is referring to a specific, understood set of stairs — for example, the stairs in a building where the friend usually is.

In Arabic, it is very common to use the definite article when the thing is known from context. So:

• الدرج = the stairs
• المصعد = the elevator

This sounds natural in the same way English often says the stairs and the elevator in a familiar setting.

لأنها is:

• لأن = because
• ها = she / her (attached pronoun here referring to she)

So لأنها means because she.

In Arabic, after words like لأن, pronouns are usually attached as suffixes, not written as separate words. So:

• لأني = because I
• لأنك = because you
• لأنها = because she
• لأنه = because he

That is why لأنها is the normal form, not لأن هي.

In Modern Standard Arabic, لا is the normal way to negate the imperfect verb when talking about a present or habitual action.

So:

• تحب = she likes
• لا تحب = she does not like / she doesn’t like

Here the meaning is general and habitual:

• because she does not like the elevator

This is standard MSA negation.

The noun مصعد is grammatically masculine. In Arabic, nouns have grammatical gender, and many nouns are masculine unless there is a clear feminine marker such as ة.

So:

• المصعد = the elevator
• it is treated as masculine in grammar

There is nothing unusual about that here, but it is useful to remember because adjectives and pronouns referring to it would need masculine forms.

Yes, that is possible.

Arabic allows both:

• صديقتي تنزل الدرج...
• تنزل صديقتي الدرج...

The version with صديقتي first puts more focus on my friend as the topic. It can feel a bit like As for my friend, she goes down the stairs...

The verb-first version can sound a bit more neutral or more narrative in some contexts.

Both are grammatical, but the given sentence is very natural and clear for emphasizing the subject.