هي تختار هذا القلم، وليس القلم الآخر، ثم تكتب الجواب في الدفتر.

Because هي means she, and تختار is the 3rd person feminine singular form of the verb اختار (to choose).

So:

• هو يختار = he chooses
• هي تختار = she chooses

In the present tense, Arabic verbs change depending on the subject, and the تـ at the beginning here marks the feminine singular form.

In Arabic, the subject pronoun is often optional because the verb already tells you who is doing the action.

So both of these can work:

• هي تختار هذا القلم
• تختار هذا القلم

Adding هي can give:

• extra clarity
• emphasis
• smoother contrast with other people if needed

So هي is not required, but it is perfectly natural.

Because قلم (pen) is a masculine noun.

Arabic demonstratives must match the gender of the noun:

• هذا = this for masculine singular
• هذه = this for feminine singular

So:

• هذا القلم = this pen
• هذه السيارة = this car

Since قلم is masculine, هذا is the correct choice.

In Arabic, demonstratives like هذا and هذه usually come before the noun.

So Arabic says:

• هذا القلم = literally this the-pen

This is just the normal Arabic pattern for this/that + noun.

وليس is made of:

• و = and
• ليس = is not / not

In this sentence, وليس القلم الآخر means something like:

• and not the other pen
• more naturally in English: not the other pen

It is being used to make a contrast:

• she chooses this pen
• not the other one

So it is a natural Arabic way to say not the other pen after mentioning one option.

Because in Arabic, adjectives normally come after the noun they describe.

So:

• القلم الآخر = the other pen

Here:

• القلم = the pen
• الآخر = the other

Arabic word order is:

• noun first
• adjective second

not the other way around.

Because adjectives in Arabic must match the noun in definiteness as well as gender and number.

Since the noun is definite:

• القلم = the pen

the adjective must also be definite:

• الآخر = the other

So:

• القلم الآخر = the other pen

If the noun were indefinite, the adjective would also be indefinite.

ثم means then, and it shows sequence: one action happens, and after that, the next action happens.

So:

• هي تختار هذا القلم ... ثم تكتب الجواب = She chooses this pen ... then writes the answer

If you used و instead, it would just mean and, without emphasizing the order as clearly.

So ثم is used because the sentence wants to show:

1. first she chooses the pen
2. after that she writes

Because the subject is still هي (she).

Arabic often keeps the same subject across connected actions unless a new subject is introduced. So both verbs refer to the same person:

• هي تختار = she chooses
• ثم تكتب = then she writes

Even though هي is not repeated before تكتب, the verb form still shows the same feminine singular subject.

الجواب means the answer.

It is a common word in MSA. Another common word is الإجابة, which can also mean the answer or the response.

So both can be possible in many contexts, but here الجواب is perfectly natural and straightforward.

Because في means in, and الدفتر means the notebook.

So:

• في الدفتر = in the notebook

This is a standard prepositional phrase:

• في
  • place/container/location

Examples:

• في البيت = in the house
• في الكتاب = in the book
• في الدفتر = in the notebook

Because the sentence is talking about a specific notebook, or at least treating it as known in context.

Arabic often uses the definite article الـ when the object is understood or already identifiable.

So:

• في الدفتر = in the notebook
• في دفتر = in a notebook

Both are grammatically possible, but they mean different things.

A simple breakdown is:

• هي = subject pronoun = she
• تختار = verb = chooses
• هذا القلم = direct object phrase = this pen
• وليس القلم الآخر = contrast phrase = and not the other pen
• ثم = connector = then
• تكتب = verb = writes
• الجواب = direct object = the answer
• في الدفتر = prepositional phrase = in the notebook

So the sentence is basically:

subject + verb + object + contrast + then + verb + object + prepositional phrase

Yes. A very natural version would be:

تختار هذا القلم، وليس القلم الآخر، ثم تكتب الجواب في الدفتر.

This still clearly means She chooses this pen, not the other pen, then writes the answer in the notebook, because the verb forms already show the subject is she.

Including هي just makes the subject more explicit.

In fully vocalized formal Arabic, it would typically be:

هي تختارُ هذا القلمَ، وليسَ القلمَ الآخرَ، ثمَّ تكتبُ الجوابَ في الدفترِ.

A learner might notice:

• تختارُ and تكتبُ end in ـُ because they are present-tense verbs in this context
• القلمَ and الجوابَ are direct objects, so they take the accusative
• الدفترِ comes after the preposition في, so it takes the genitive

In normal everyday writing, these short vowel endings are usually not written.

Because ليس is a common way to negate a nominal expression or make a contrast like not X.

Here the phrase is elliptical: the full idea is something like:

• it is not the other pen

So وليس القلم الآخر works naturally as a contrastive phrase.

Using لا here would not be the normal choice for this exact structure.

In this exact form, it is closer to SVO at the start:

• هي = subject
• تختار = verb
• هذا القلم = object

So it begins as Subject–Verb–Object.

But Arabic also often allows the subject pronoun to be dropped, which would give:

• تختار هذا القلم

That feels more verb-initial.

Arabic word order is flexible, but this sentence as written begins with an explicit subject pronoun, so learners often experience it as SVO.

A natural reading would group it like this:

هي تختار هذا القلم | وليس القلم الآخر | ثم تكتب الجواب في الدفتر

The pauses help show the meaning:

1. she chooses this pen
2. not the other pen
3. then she writes the answer in the notebook

So punctuation and phrasing support the contrast and sequence.