لو نزلت من المبنى الآن، لوصلت إلى البنك قبل الساعة العاشرة.

لو is a conditional particle meaning if, but not the most neutral kind of if.

In this sentence, it introduces a hypothetical situation:

لو نزلت من المبنى الآن، لوصلت إلى البنك قبل الساعة العاشرة.
= If you left the building now, you would reach the bank before ten o’clock.

So لو often suggests an imagined, unreal, or less direct condition, rather than a simple real future condition.

This is one of the most important things to notice.

After لو, Arabic often uses past-tense verb forms to express a hypothetical meaning, not actual past time. So the forms look past, but the meaning is more like English would.

Pattern:

لو + past verb ... لَ + past verb

This often corresponds to:

if ... would ...

So here:

• نزلت literally looks like went down / got out
• لوصلت literally looks like arrived

But together they mean:

If you were to leave now, you would arrive...

So the tense form is grammatical; the actual time reference comes from the whole conditional structure and from الآن.

That لـ is called لام الجواب or لام جواب لو. It marks the result clause of the conditional sentence.

So:

• لو نزلت... = if you left...
• لوصلت... = you would arrive...

This لـ is very common in formal Arabic after لو, and it helps signal the consequence or result of the condition.

A learner-friendly way to think about it is:

• لو introduces the if-clause
• لـ on the next verb helps mark the would-clause

This is a very common question, because both can be translated as if.

A simple distinction is:

• إذا = a real, expected, or open condition
• لو = a hypothetical, imagined, or less direct condition

Compare:

إذا نزلت من المبنى الآن، ستصل إلى البنك قبل الساعة العاشرة.
= If you leave the building now, you will arrive at the bank before ten.

This sounds like a real possibility.

But:

لو نزلت من المبنى الآن، لوصلت إلى البنك قبل الساعة العاشرة.
= If you left the building now, you would arrive at the bank before ten.

This sounds more hypothetical.

So if the speaker is talking about a realistic plan, إذا is often better. If the speaker is imagining a situation, لو fits well.

Without short vowels, نزلت and وصلت are ambiguous in writing. They can represent several forms, depending on vocalization.

For example, نزلت could be:

• نَزَلْتُ = I went down
• نَزَلْتَ = you masculine singular went down
• نَزَلْتِ = you feminine singular went down
• نَزَلَتْ = she went down

The same applies to وصلت.

So context tells you the intended subject unless vowel marks are written.

If the intended meaning is you masculine singular, the fully vocalized sentence would be:

لَوْ نَزَلْتَ مِنَ الْمَبْنَى الآنَ، لَوَصَلْتَ إِلَى الْبَنْكِ قَبْلَ السَّاعَةِ الْعَاشِرَةِ.

If it meant you feminine singular, it would be:

لَوْ نَزَلْتِ ... لَوَصَلْتِ

Yes. The basic meaning of نزل is to go down, descend, or get down.

With من, it often means:

• come down from
• get out of
• leave, especially with a sense of movement downward or out from a place

So نزل من المبنى is literally something like went down from the building, but in natural English it often means left the building or came down from the building.

If you wanted a more neutral verb for exit, Arabic could also use خرج من المبنى.

So:

• نزل من المبنى = emphasizes going down/out
• خرج من المبنى = emphasizes exiting

In Modern Standard Arabic, the normal pattern is:

وصل إلى + place

So:

• وصل إلى البنك = arrived at the bank / reached the bank

The preposition إلى marks the destination.

In some nonstandard or spoken usage, people may omit the preposition, but for a learner of MSA, وصل إلى is the safest and most standard structure to use.

قبل means before.

Then الساعة العاشرة literally means the tenth hour, which is the standard Arabic way to say ten o’clock.

So:

• قبل الساعة العاشرة = before ten o’clock

As for العاشرة, it is feminine because it agrees with الساعة, and الساعة is a feminine noun.

So Arabic is really saying:

• the tenth hour
• not just bare ten

That is why the ordinal is feminine: العاشرة, not العاشر.

الآن means now, and here it modifies the first verb, نزلت.

So the sense is:

If you left the building now...

Yes, Arabic word order is flexible, and الآن could be moved to another natural position, such as:

لو نزلت الآن من المبنى، لوصلت إلى البنك قبل الساعة العاشرة.

That also works. The original sentence is natural; it just places الآن after من المبنى.

Yes, that is the most natural interpretation.

Because the sentence uses لو, it presents the action as hypothetical. So the speaker is not saying the person is actually leaving. The speaker is imagining the result:

If you left now, you would get there before ten.

So the sentence suggests that the person is still in the building at the moment of speaking, or at least that the leaving is being considered rather than described as a fact.

البنك is very common and widely accepted in Modern Standard Arabic. It is a normal word for bank.

المصرف is also correct and is often more formal or more classically Arabic in flavor.

So both are possible:

• البنك = very common and natural
• المصرف = more formal or institutional

For most learners, البنك is perfectly fine in a sentence like this.