منذ أن وضعت الأصيص قرب النافذة، ينمو البرعم.

Together, منذ أن introduces a time clause meaning since.

So the structure is:

• منذ = since
• أن + verb = a clause, here something like that/when [someone] put

In this sentence, it marks the starting point for the later action: the growing began from the time the pot was placed near the window.

Because it refers to the completed action that started the situation.

The idea is:

• first, the pot was placed near the window
• after that, the bud started growing / has been growing

After منذ أن, Arabic very naturally uses a past verb to express that starting event.

In unvowelled Arabic, وضعت is ambiguous by itself. It can represent:

• وضعتُ = I put
• وضعتَ = you (masculine singular) put
• وضعتْ = she put

So you usually know from:

• context
• the translation already given
• vowel marks, if they are written

If the intended meaning is I put, then the fully marked form would be وضعتُ.

Because Arabic uses the imperfect/present form for an action that is ongoing.

Here ينمو means the bud is growing or has been growing, depending on how you express it in English. Arabic and English do not match perfectly in tense usage here. English often prefers:

• has been growing

But Arabic can simply use the present/imperfect to show a continuing action from that earlier point until now.

الأصيص is the direct object of وضعت.

So the structure is:

• وضعت = put
• الأصيص = the pot / flowerpot

In other words, it is the thing that was put somewhere.

In fully inflected Arabic, it would be in the accusative case: الأصيصَ.

قرب here means near and functions as an expression of place.

So:

• قرب = near / close to
• النافذة = the window

Together, قرب النافذة means near the window.

A useful way to think about it is that قرب behaves like a noun of location or an adverbial expression of place, and the noun after it is linked to it in a genitive relationship.

Because it comes after قرب in a construction like قربَ النافذةِ.

In formal grammar, قرب is treated as a location expression, and the following noun is its complement in the genitive, similar to an iḍāfa-like relationship.

So in full case marking:

• قربَ = accusative as an adverbial of place
• النافذةِ = genitive

Both are possible.

• ينمو البرعم = a verbal sentence, more naturally The bud is growing
• البرعم ينمو = a nominal sentence, often a little more topic-focused, like As for the bud, it is growing

Arabic very often starts a sentence with the verb, especially in straightforward narration. So ينمو البرعم is completely normal.

Because they are definite: the speaker is referring to specific things, not just any pot, any window, or any bud.

So the sentence sounds like it is talking about known items in the situation:

• the flowerpot
• the window
• the bud

If the meaning were more general or indefinite, Arabic could leave off الـ.

In sentences like this, منذ أن is a very common and clear way to say since followed by a clause.

Using أن helps introduce the following verb phrase smoothly. In learner terms, it is best to treat منذ أن as a common pattern meaning since [something happened].

So even if you later encounter some variation, منذ أن + past verb is a very useful model to remember.

If the intended meaning is Since I put the flowerpot near the window, the bud is growing, the endings would be approximately:

• وضعتُ = I put
• الأصيصَ = direct object, accusative
• قربَ = adverbial expression of place, accusative
• النافذةِ = genitive after قرب
• ينمو البرعمُ = البرعمُ is the subject, nominative

So the important grammatical pattern is:

• past verb + object + place expression
• then present verb + subject

Yes. If you only look at the unvowelled spelling وضعت, that reading is also possible.

That is one reason Arabic learners need to rely on:

• context
• translation
• vowel marks when available

So without extra context, وضعت is not enough by itself to tell you whether the subject is I, you, or she.