عندما يرن جرس الباب، تذهب أمي إلى الباب وتفتح للضيفة.

عندما is a time word meaning when.

It introduces a time clause, so عندما يرن جرس الباب means when the doorbell rings.

A useful thing to know is that عندما is commonly followed by a verb in the present tense in Modern Standard Arabic, even when English might translate it in a more flexible way.

You can think of the structure as:

• عندما + present verb
• When + something happens

It is very common in MSA narrative and formal writing.

Because in Arabic, after عندما, the verb is often in the present tense to describe an action that happens at that time.

So:

• عندما يرن جرس الباب = when the bell rings

Even if the whole sentence describes a repeated habit or a general situation, Arabic still naturally uses the present here.

Also, يرن is a 3rd person masculine singular verb because its subject is جرس and جرس is grammatically masculine singular.

This is an iḍāfa construction, often called a genitive/possessive construction.

جرس الباب literally works like:

• bell of the door
• in natural English: the doorbell

In an iḍāfa:

• the first noun usually does not take ال
• the second noun can be definite

So:

• جرس الباب = the doorbell
• not الجرس الباب

If fully vowelled, it would be:

• جرسُ البابِ

The second noun الباب makes the whole phrase definite, so جرس الباب already means the doorbell.

Because أمي is feminine singular: my mother.

In the present tense, a feminine singular subject takes the تـ form:

• هي تذهب
• أمي تذهب

So تذهب أمي means my mother goes.

Arabic verbs agree with the subject in gender and number, and since أمي is feminine singular, تذهب is the correct form.

Because Arabic verbs already include subject information.

تذهب already tells you the subject is:

• she
• or sometimes you depending on context

Once أمي appears, the meaning is clear: my mother goes.

So Arabic often does not need an extra subject pronoun like English does. Saying هي تذهب أمي would be wrong here.

The verb ذهب means to go, and when you say where someone goes, Arabic normally uses the preposition إلى = to.

So:

• تذهب إلى الباب = she goes to the door

This is just the normal pattern of the verb:

• ذهب إلى... = went to...
• يذهب إلى... = goes to...

So إلى is required here to mark the destination.

Because the sentence is talking about two related but different things:

• جرس الباب = the doorbell
• إلى الباب = to the door

Even though English also repeats door in doorbell and to the door, learners sometimes notice it more in Arabic because the wording is very literal.

So the repetition is completely natural.

The object is understood from context: the door.

Arabic often leaves out an object if it is obvious. Since the previous part already mentions الباب, it is easy to understand that تفتح means she opens the door.

So:

• وتفتح للضيفة = and she opens for the female guest

If you want to make the object explicit, you could say:

• وتفتح الباب للضيفة

That is also correct and very clear.

لـ usually means for or to.

Here, تفتح للضيفة means something like:

• she opens for the female guest
• in smoother English: she opens the door for the female guest

This is a common Arabic pattern:

• فتح له / لها = opened for him / her

Also, للضيفة is just a combination of:

• لـ + الضيفة

When لـ comes before ال, the spelling becomes:

• للـ

So:

• لِلضيفة = for the female guest

Because ضيفة is the feminine form, meaning female guest.

So:

• ضيف = male guest / guest in masculine form
• ضيفة = female guest

The sentence specifically refers to a female guest, so الضيفة is used.

If the guest were male, you would say:

• وتفتح للضيف

Because the sentence is referring to a specific, identifiable guest in the situation.

In Arabic, it is very normal to use the definite form when the person is understood from context. Once the doorbell rings, the guest at the door is treated as a known person in that situation.

So للضيفة means:

• for the female guest
• not just for a female guest in a vague sense

If you said لضيفة, it would sound less natural here unless you were emphasizing that she is just some unspecified guest.

Yes, this is very normal in Modern Standard Arabic.

The sentence uses a common verb-first order:

• يرن جرس الباب
• تذهب أمي
• تفتح

Arabic often prefers verb + subject in formal written style.

You could also sometimes see subject + verb, for example:

• أمي تذهب إلى الباب

That is also grammatical, but the version in your sentence sounds very natural and standard in MSA prose.

Yes, absolutely.

Both are correct:

• وتفتح للضيفة
• وتفتح الباب للضيفة

The shorter version omits الباب because it is obvious. The longer version makes the sentence more explicit.

So the difference is mainly:

• shorter, understood from context
• more explicit

Both are natural Arabic.