عندما يكمل المتدرب الدورة المسائية، يستلم شهادة إتمام.

عندما means when and introduces a time clause.

In this sentence, it sets up the event that triggers the next one: when the trainee completes the evening course, he receives a certificate of completion.

It overlaps with إذا, but there is a slight difference in feel:

• عندما often sounds more like when, referring to the time at which something happens
• إذا often has a more conditional feel, somewhere between if and when

So عندما is very natural here because the sentence is describing what happens at that point in time.

Arabic often uses the imperfect verb form (what learners usually call the present tense) for:

• habitual actions
• general truths
• future actions after words like when

So عندما يكمل... يستلم... means something like:

• when he completes..., he receives...
• or more generally whenever he completes..., he receives...

This is normal Arabic usage. The verbs are not referring to the present moment; they are describing an expected sequence of events.

Because Arabic spelling usually leaves out short vowels, يكمل can be ambiguous on its own.

Here, the intended reading is يُكْمِلُ = he completes / finishes.

You can tell from the context because it is followed by a direct object:

• يكمل الدورة = he completes the course

If it were the intransitive verb meaning to be complete, it would usually not take a direct object like الدورة.

So the sentence structure tells you the correct reading.

المتدرب means the trainee, and grammatically it is an active participle.

It comes from the verb تدرّب = to train / to undergo training.

So متدرّب literally means someone who is training or a trainee.

In this sentence it is the subject of يكمل, so if the text were fully vocalized, it would be:

• المتدرّبُ

with a nominative ending.

Because الدورة is a feminine noun.

In Arabic, adjectives must agree with the noun they describe in:

• gender
• number
• definiteness
• case

So:

• الدورة = feminine, singular, definite
• المسائية must also be feminine, singular, definite

That is why you get:

• الدورة المسائية = the evening course

Also, المسائية is the adjective evening/evening-related, built from مساء = evening.

Yes. الدورة المسائية is the direct object of يكمل.

The verb يُكْمِلُ means to complete, so it needs something that is being completed:

• يكمل الدورة = he completes the course

If the sentence were fully vocalized, both words would be in the accusative because:

• الدورةَ is the noun being acted on
• المسائيةَ is its adjective and must match it

So the fully marked phrase would be:

• الدورةَ المسائيةَ

Because Arabic verbs already include the subject information.

يستلم by itself means:

• he receives
• or he takes delivery of

So Arabic does not need a separate هو here.

The subject is understood to be the same person already mentioned, namely المتدرب.

You could add هو for emphasis, but it is not necessary:

• ... فهو يستلم شهادة إتمام

That would sound more emphatic, not more basic or more correct.

Because the sentence means a certificate of completion, not the certificate of completion.

Arabic uses the indefinite form when the thing is not being treated as a specifically identified item already known to the listener.

So:

• شهادة إتمام = a certificate of completion
• الشهادة would mean the certificate

Here the idea is that once the trainee finishes, he receives some certificate of that type, so the indefinite form is natural.

It is an iḍāfa construction, often called a genitive construction.

This is the common Arabic pattern for expressions like:

• certificate of completion
• teacher of Arabic
• door of the house

In شهادة إتمام:

• شهادة = certificate
• إتمام = completion

Together they mean:

• certificate of completion

Grammatically:

• the first noun is شهادة
• the second noun is إتمام
• the second noun is in the genitive
• the whole phrase gets its overall definiteness from the second noun

Because إتمام is indefinite here, the whole phrase is indefinite.

A fully vocalized version would be:

عِندَما يُكْمِلُ المُتَدَرِّبُ الدَّوْرَةَ المَسائِيَّةَ، يَسْتَلِمُ شَهادَةَ إِتْمامٍ.

This helps show the grammar more clearly:

• المتدرّبُ = subject, nominative
• الدورةَ المسائيّةَ = direct object + adjective, accusative
• شهادةَ = direct object of يستلم, accusative
• إتمامٍ = second part of the iḍāfa, genitive

Not strictly.

In modern Arabic writing, a comma is often used to separate the time clause from the main clause, especially in a sentence like this:

• عندما يكمل المتدرب الدورة المسائية، يستلم شهادة إتمام.

That punctuation is normal and helpful, but Arabic punctuation is a modern writing convention, not something built into the grammar itself. The sentence would still be understandable without the comma.