بعد الدرس فهمت السؤال وكتبت الجواب على الصفحة.

With full vowel marks, it is:

بَعْدَ الدَّرْسِ فَهِمْتُ السُّؤَالَ وَكَتَبْتُ الجَوَابَ عَلَى الصَّفْحَةِ.

A careful pronunciation would be roughly:

baʿda d-darsi fahimtu s-suʾāla wa-katabtu al-jawāba ʿalā ṣ-ṣafḥati

A few notes:

• فهمتُ = fahimtu = I understood
• كتبتُ = katabtu = I wrote
• The final short vowels often disappear in normal pause, but they are useful for understanding the grammar.

بعد الدرس means after the lesson.

Grammatically:

• بعدَ is a time expression meaning after
• الدرسِ is the noun after it, in the genitive
• Together they form an iḍāfa-like construction: literally something like the after of the lesson

So:

• بعدَ = accusative here because it is functioning as an adverbial expression of time
• الدرسِ = genitive because it is linked to بعد

That is why the fully vocalized form is بعدَ الدرسِ.

Because they are in the past tense and the ending -تُ marks I.

So:

• فهمتُ = I understood
• كتبتُ = I wrote

This is one of the basic Arabic past-tense endings:

• فهمتُ = I understood
• فهمتَ = you understood (masculine singular)
• فهمتِ = you understood (feminine singular)
• فهمتْ = she understood

In unvocalized writing, all of these can look like فهمت, so the short vowels matter.

Yes. Without vowel marks, فهمت could represent more than one form.

For example:

• فهمتُ = I understood
• فهمتْ = she understood

The same is true for كتبت:

• كتبتُ = I wrote
• كتبتْ = she wrote

You know it means I here from context and, if fully vocalized, from the final vowel:

• فهمتُ = I understood
• كتبتُ = I wrote

So this sentence is first person singular.

Because Arabic usually puts the subject inside the verb itself.

So instead of saying:

• أنا فهمتُ
• أنا كتبتُ

Arabic can simply say:

• فهمتُ
• كتبتُ

The pronoun أنا is optional and is usually added only for emphasis, contrast, or clarity.

So this sentence sounds natural without أنا.

Because Arabic often uses the definite article when referring to specific, understood items in context.

Here:

• السؤال = the question
• الجواب = the answer

This suggests a particular question and its answer, probably already known from the situation.

English and Arabic do not always use definiteness in exactly the same way, so even if English might sometimes say a question or an answer, Arabic may prefer the question and the answer if they are contextually identifiable.

They are both direct objects, so they are in the accusative case.

Fully vocalized:

• فهمتُ السُّؤَالَ
• كتبتُ الجَوَابَ

The final -َ on each noun is the accusative ending.

In normal unvocalized Arabic, you usually do not see that ending, but grammatically it is still there.

Yes. The و simply means and, and the subject continues naturally.

So:

• فهمتُ السؤالَ = I understood the question
• وكتبتُ الجوابَ = and I wrote the answer

Arabic does not need to repeat أنا or any separate subject pronoun here. The verbs already show the subject.

This is very normal Arabic sentence structure.

Because على is the natural choice for writing on a page or surface.

So:

• على الصفحة = on the page

This matches the physical idea of writing on a surface.

By contrast, في الصفحة would usually mean something more like:

• in the page
• within the page
• as part of the page’s contents

For actual writing placed on the page, على الصفحة is the idiomatic choice.

Because Arabic has sun letters and moon letters.

In this sentence:

• الدَّرس: د is a sun letter, so ال is pronounced ad-/d-
• السُّؤال: س is a sun letter, so ال is pronounced as-/s-
• الصَّفحة: ص is a sun letter, so ال is pronounced aṣ-/ṣ-
• الجواب: ج is a moon letter, so the l sound stays: al-jawāb

So the spelling stays the same, but the pronunciation changes depending on the first consonant of the noun.

Yes, the sentence begins with a time expression.

So the structure is:

• بعد الدرس = after the lesson
• فهمت السؤال = I understood the question
• وكتبت الجواب على الصفحة = and wrote the answer on the page

Starting with the time phrase is very natural in Arabic. It sets the scene first, much like English can do:

• After the lesson, I understood the question...

Arabic word order is fairly flexible, and fronting time expressions is common.

Both can mean answer, but they are not always used in exactly the same way.

• جواب is a very common general word for answer/reply
• إجابة also means answer, often with a slightly more formal or abstract feel

In many contexts, both are possible. So you could often say:

• كتبتُ الجواب
• كتبتُ الإجابة

But الجواب is very natural and straightforward here.

It is perfectly good Modern Standard Arabic.

Most educated Arabic speakers would understand it easily, and much of it is also close to everyday usage. However, in spoken dialects, people might choose different words or slightly different grammar.

So as a learner of MSA, this sentence is completely normal and useful.