خواهرم یک شلوار دیگر هم پوشید تا سایز درست را پیدا کند.

خواهر means sister, and the ending ـم is the attached pronoun meaning my.

So:

• خواهر = sister
• خواهرم = my sister

This kind of possessive ending is very common in Farsi:

• کتابم = my book
• دوستم = my friend
• برادرم = my brother

Farsi often leaves out subject pronouns when they are clear from context or from the verb.

In this sentence, پوشید and کند are both third-person singular, so the subject can be understood as she. Since خواهرم is already mentioned, there is no need to add او.

So instead of saying:

• خواهرم ... او ...

Farsi naturally just says:

• خواهرم ...

This is very common and natural.

In Farsi, شلوار is grammatically singular, even though in English pants / trousers is plural in form.

So:

• یک شلوار = a pair of pants / one pair of trousers

This is similar to how some nouns do not match English number patterns exactly. In normal Persian, شلوار works as a regular singular noun.

It means another pair of pants.

Breakdown:

• یک = one / a
• شلوار = pants, trousers
• دیگر = other / another

So یک شلوار دیگر literally means one other pair of pants, which is the natural Persian way to say another pair of pants.

هم usually means also, too, or sometimes even, depending on context.

In یک شلوار دیگر هم پوشید, it gives the sense that she also put on / tried on another pair of pants, probably after trying one before.

So the nuance is something like:

• she put on another pair of pants too
• she also tried another pair

It often adds the idea that this action is one in a series.

In Persian, هم often comes after the word or phrase it is associated with.

Here it follows یک شلوار دیگر, so it emphasizes that another pair of pants was also involved.

• یک شلوار دیگر هم پوشید

This word order is very natural in Persian. English does not match it exactly word-for-word, so it is better to learn it as a common placement pattern.

It literally comes from پوشیدن, which means to wear or to put on, depending on context.

In this sentence, because she is trying to find the right size, پوشید is best understood as:

• put on
• tried on

So although the basic verb is the normal verb for wearing clothes, the context makes it clear that this is about trying on clothes.

پوشید is the simple past form of پوشیدن.

It is third-person singular:

• من پوشیدم = I put on / wore
• تو پوشیدی = you put on / wore
• او پوشید = he/she put on / wore

So here پوشید means she put on or she tried on.

Here تا means so that or in order to.

It connects the first action to a purpose:

• خواهرم یک شلوار دیگر هم پوشید = My sister put on another pair of pants too
• تا سایز درست را پیدا کند = so that she could find the right size

So تا introduces the goal or purpose of the action.

After تا meaning so that / in order to, Persian commonly uses the subjunctive form.

So:

• پیدا کند = that she find / so that she can find / so that she could find

This does not translate word-for-word into English, but grammatically it is very normal in Persian.

The verb کند is the subjunctive form of کردن in third-person singular. Since پیدا کردن means to find, پیدا کند means find in this kind of purpose clause.

Because پیدا کردن is a compound verb.

Many Persian verbs are made of:

• a non-verbal element
• plus a light verb such as کردن, شدن, دادن, etc.

Here:

• پیدا = found, apparent, located
• کردن = to do
• پیدا کردن = to find

So in conjugation, the second part changes:

• پیدا می‌کنم = I find
• پیدا کرد = he/she found
• پیدا کند = he/she may find / find (subjunctive)

را marks a specific direct object.

Here, سایز درست is the object of پیدا کند, and it is understood as a specific thing: the right size.

So:

• سایز درست را پیدا کند = find the right size

In many cases, if the object is definite or specific, Persian uses را.

Compare:

• کتاب را خواندم = I read the book
• دوستم را دیدم = I saw my friend

In Persian, adjectives normally come after the noun.

So:

• سایز درست = right size
• کتاب خوب = good book
• خانه بزرگ = big house

In speech, there is an ezafe sound between them, so this is pronounced roughly as سایزِ درست, even though the short -e sound is usually not written.

Yes, in pronunciation there is.

Persian usually links a noun to a following adjective with ezafe, pronounced like a short -e:

• شلوارِ دیگر
• سایزِ درست

But this short vowel is often not written, especially after a consonant. So learners need to know that it is present in speech even when invisible in the script.

In this sentence, another is the best interpretation.

دیگر can have several related uses, such as other, another, or sometimes part of expressions meaning no longer or else. But in یک شلوار دیگر, it naturally means:

• another pair of pants
• one more pair of pants

That is the most straightforward reading here.

The basic Persian order is usually subject + object + verb.

Here we get:

• خواهرم = subject
• یک شلوار دیگر هم = object/adverbial phrase
• پوشید = verb
• تا سایز درست را پیدا کند = purpose clause

So Persian keeps the main verb پوشید near the end of the main clause, and the verb کند at the end of the subordinate clause. This is very typical of Persian sentence structure.

Yes, it is natural and clear.

In more conversational Persian, someone might also use a verb like امتحان کرد for tried on, but پوشید works well here because the context makes the meaning clear.

So this sentence is a good, natural example of how Persian expresses:

• putting on another item of clothing
• for the purpose of finding the right size