لا يستلم صديقي النظارة الطبية إلا إذا كانت جاهزة.

In this sentence, يستلم means receives, takes delivery of, or picks up.

So in context, it is not just general receiving in an abstract sense. It more specifically suggests that your friend is collecting the glasses when they are ready.

The verb is from Form X: استلم. In different contexts, it can mean:

• receive
• take over
• accept delivery of

Here, picks up / receives is the natural meaning.

لا is used here to negate the imperfect verb يستلم.

So:

• يستلم = he receives / he picks up
• لا يستلم = he does not receive / he does not pick up

This usually gives a present, habitual, or general meaning.

So the sentence sounds like a general rule or habit:

• My friend does not pick up the medical glasses unless they are ready.

If you wanted a simple past meaning like did not pick up, Arabic would usually use لم + imperfect:

• لم يستلم

Because of the meaning and the sentence structure.

• يستلم is the verb: receives / picks up
• صديقي is the one doing the action: my friend
• النظارة الطبية is the thing being received: the medical glasses

So:

• صديقي = subject
• النظارة الطبية = direct object

A native English speaker may expect the subject to come first, but Arabic often puts the verb first, especially in formal written language.

Because verb-subject-object order is very common in Modern Standard Arabic.

So this structure is normal:

• لا يستلم صديقي النظارة الطبية

Literally:

• does not receive my friend the medical glasses

But in natural English:

• My friend does not receive/pick up the medical glasses

Arabic could also say:

• صديقي لا يستلم النظارة الطبية

That is also correct, but it gives a slightly different emphasis because the subject is placed first.

Because صديقي means my friend.

It is made of:

• صديق = friend
• ـي = my

So:

• صديق = a friend / friend
• صديقي = my friend

The ـي is a possessive suffix.

Also, once this suffix is attached, the noun becomes definite, because my friend is already specific.

Arabic often uses a singular noun where English uses a plural form.

Here, النظارة can refer to a pair of glasses. So even though English says glasses, Arabic may use a singular word.

That is very common with items that come in pairs or are treated as one object.

So:

• النظارة = the glasses / the pair of glasses / the spectacles

If you used النظارات, that would more naturally suggest multiple pairs of glasses.

Because الطبية is an adjective describing النظارة, and Arabic adjectives must agree with the noun they describe.

Here, النظارة is:

• singular
• feminine
• definite

So the adjective must also be:

• singular
• feminine
• definite

That gives:

• النظارة الطبية

Agreement includes:

• gender
• number
• definiteness
• case

So the ـة in الطبية is there because the noun is feminine.

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

So:

• النظارة الطبية = the medical glasses

This is the normal pattern:

• noun first
• adjective second

Also, if the noun is definite with ال, the adjective must also be definite with ال.

Compare:

• نظارة طبية = medical glasses / a medical pair of glasses
• النظارة الطبية = the medical glasses

In this sentence, إلا إذا means something like unless or except if.

So:

• لا يستلم ... إلا إذا ... means
• he does not pick it up unless ...

This combination is common in Arabic:

• a negative main clause
• followed by إلا إذا to introduce the only exception

So the logic is:

• he does not receive it
• except if it is ready

In English, unless is usually the most natural translation in a sentence like this.

Because the thing being referred to is feminine: النظارة.

In the clause:

• إذا كانت جاهزة

the subject is understood as it, referring back to النظارة.

Since النظارة is feminine, Arabic uses:

• كانت = it was / it is being (feminine)

If the noun were masculine, you would expect كان instead.

Because it describes the understood subject of كانت, which refers back to النظارة.

So the idea is:

• إذا كانت النظارة جاهزة = if the glasses are ready

The noun النظارة is feminine singular, so the adjective must also be feminine singular:

• جاهزة

If the noun were masculine, the adjective would be masculine:

• جاهز

This is a very common Arabic pattern.

After إذا, Arabic often uses a verb form that looks like the past, even when the meaning in English is present or future, especially in conditions and general statements.

So:

• إذا كانت جاهزة can naturally mean
• if it is ready or
• if it happens to be ready

This does not necessarily mean a past event in English.

Also, with adjectives and states, Arabic often uses كان-type structures naturally:

• كانت جاهزة = it was/was being ready, but in this context: if it is ready

So this is normal idiomatic Arabic, not a literal past tense in the English sense.

Yes.

In كانت جاهزة, the subject is not written separately. It is understood as a hidden pronoun meaning she/it, referring to النظارة.

So grammatically, the clause is like:

• إذا كانت هي جاهزة = if it is ready

But Arabic usually leaves that pronoun unstated because it is already clear from the verb form and the context.

In normal Arabic writing, short vowel endings are usually omitted, but the grammatical roles are still there.

The fully analyzed roles are:

• يستلمُ — verb
• صديقي — subject, so nominative
• النظارةَ — direct object, so accusative
• الطبيةَ — adjective describing النظارة, so it matches it in case and is also accusative
• كانت — verb
• hidden feminine pronoun — the subject of كانت
• جاهزةً — predicate of كان, so accusative

A fully vocalized version would be approximately:

لا يَسْتَلِمُ صديقي النَّظَّارَةَ الطِّبِّيَّةَ إِلَّا إِذا كانَتْ جاهِزَةً

In ordinary writing, those final vowels are usually not shown.

Yes, absolutely.

That would be a more explicit version:

• لا يستلم صديقي النظارة الطبية إلا إذا كانت النظارة جاهزة

But Arabic often avoids repeating a noun when it is already clear, so it is more natural to say:

• إلا إذا كانت جاهزة

The noun النظارة is understood from the earlier part of the sentence.

So the shorter version is normal and natural.