من هنوز بلیت قطار را نخریده ام، چون منتظر خواهرم هستم.

Yes. In Persian, the verb ending already shows the subject, so من is often optional.

• نخریده‌ام already tells you the subject is I
• هستم also tells you I am

So this sentence could also be said naturally as:

هنوز بلیت قطار را نخریده‌ام، چون منتظر خواهرم هستم.

Using من adds a little emphasis or clarity, but it is not required.

هنوز means still or yet, depending on the sentence.

In this negative sentence, it is best understood as yet:

• هنوز نخریده‌ام = I haven’t bought it yet

In an affirmative sentence, it often means still:

• هنوز منتظرم = I am still waiting

So هنوز is a very common word for talking about something that has not happened yet or is still continuing.

نخریده‌ام is the negative present perfect form of خریدن (to buy).

It breaks down like this:

• خرید = buy
• خریده = bought
• خریده‌ام = I have bought
• نخریده‌ام = I have not bought

So literally it means I have not bought, but in English the most natural translation here is often I haven’t bought ... yet.

You may also see it written as:

• نخریده‌ام
• نخریده ام

The first is more standard, using a half-space.

Because the meaning is different.

• نخریده‌ام = I haven’t bought
• نمی‌خرم = I don’t buy / I’m not buying / I won’t buy, depending on context

In this sentence, the speaker means the action has not happened up to now. That is why the present perfect is the natural choice.

With هنوز, Persian very often uses this kind of structure:

• هنوز ... نکرده‌ام
• هنوز ... نرفته‌ام
• هنوز ... نخریده‌ام

These usually match English haven’t ... yet.

را is the direct object marker. It usually marks a specific or definite direct object.

Here, بلیت قطار را means the speaker is talking about a particular ticket, not just any ticket in general.

Compare:

• بلیت قطار خریدم = I bought a train ticket
• بلیت قطار را خریدم = I bought the train ticket / I bought the specific train ticket

A useful point: را comes after the whole object phrase, not just after the first noun.

Also, in spoken Persian, را is often pronounced رو.

Yes. This is an example of ezafe.

So بلیت قطار is pronounced:

بلیتِ قطار

That -e sound links the two nouns and shows a relationship like:

• ticket of train
• train ticket

In normal writing, ezafe is often not written after a consonant, but it is still pronounced.

So a learner should read:

• بلیت قطار as belit-e qatar

Because -م is an attached pronoun meaning my.

So:

• خواهر = sister
• خواهرم = my sister

Persian often attaches possessive endings directly to nouns:

• کتابم = my book
• دوستم = my friend
• خواهرم = my sister

You can also say خواهرِ من, but خواهرم is more compact and very common.

Persian does not use a separate word equivalent to English for in this structure.

The pattern is:

منتظرِ کسی/چیزی بودن = to wait for someone/something

So:

• منتظرِ خواهرم هستم = I am waiting for my sister

There is an ezafe after منتظر, even though it is usually not written in ordinary text:

• written: منتظر خواهرم هستم
• pronounced: montazer-e khâharam hastam

So English needs for, but Persian does not.

Because منتظر is not the main verb by itself here. It is more like an adjective or state: waiting / expectant.

To say I am waiting, Persian uses:

منتظر ... هستم

Literally, this is something like:

• I am in a waiting state for ...

So هستم is the form of بودن (to be) that matches I am.

This is very common in Persian:

• خسته هستم = I am tired
• آماده هستم = I am ready
• منتظر هستم = I am waiting

Because Persian is usually a verb-final language.

That means the verb often comes at the end of the clause:

• من هنوز بلیت قطار را نخریده‌ام
• منتظر خواهرم هستم

This is different from English, where the verb usually comes earlier.

A rough pattern in Persian is:

subject + other information + object + verb

So for English speakers, one of the biggest adjustments is getting used to waiting until the end of the clause for the verb.

Yes. Persian allows that.

You can say:

چون منتظر خواهرم هستم، هنوز بلیت قطار را نخریده‌ام.

This means the same thing as the original sentence.

So both orders are natural:

• هنوز بلیت قطار را نخریده‌ام، چون منتظر خواهرم هستم.
• چون منتظر خواهرم هستم، هنوز بلیت قطار را نخریده‌ام.

The choice depends on what the speaker wants to emphasize first: the result or the reason.