kaigi no mae ni, okyakusama ni watasi no meisi wo watasimasita.

They are doing two different jobs:

• 会議の前に: here, に marks a time point: before the meeting
• お客様に: here, に marks the recipient of the action: to the customer/client/guest

So in this sentence:

• 会議の前に = before the meeting
• お客様に = to the customer
• 私の名刺を = my business card
• 渡しました = handed/gave

Japanese often uses the same particle for different functions, so seeing に more than once in a sentence is very normal.

This is a very common pattern:

• Noun + の + 前に

So:

• 会議 = meeting
• の = connects meeting to before
• 前 = front / before
• に = marks the time reference

Together, 会議の前に means before the meeting.

You can use this pattern with many nouns:

• 食事の前に = before the meal
• 授業の前に = before class
• 出発の前に = before departure

Because 前 is a noun-like word, and when one noun modifies another noun in Japanese, の is often used.

So:

• 会議の前 = the meeting’s before = before the meeting

This is similar to:

• 学校の後ろ = behind the school
• 駅の近く = near the station
• 家の前 = in front of the house

In other words, の links 会議 and 前 into one phrase.

お客様 is a polite/honorific way to say customer, guest, or sometimes client.

It contains:

• お: an honorific prefix
• 客様: a respectful form related to 客

In business situations, service settings, and formal speech, お客様 is much more natural than 客.

• 客 can sound blunt or less polite
• お客様 sounds respectful

Since this sentence involves giving a business card, a polite business context is very likely, so お客様 fits very well.

私の名刺 means my business card.

Breakdown:

• 私 = I / me
• の = possessive marker, like ’s or of
• 名刺 = business card

So:

• 私の名刺 = my business card

This is one of the most basic uses of の in Japanese: showing possession or association.

Examples:

• 私の本 = my book
• 田中さんの車 = Tanaka’s car
• 会社の資料 = the company’s materials

Yes, it could be omitted if the context already makes it clear whose business card it was.

Japanese often leaves out things that are obvious from context. So in real conversation, you might hear:

• 会議の前に、お客様に名刺を渡しました。

This would still usually be understood as I gave the customer my business card, especially if the speaker is talking about their own actions.

However, 私の is included here to make it explicit that it was my business card, not someone else’s.

Because 名刺 is the direct object of the verb 渡しました.

The particle を marks the thing that is directly acted on.

So:

• 名刺を渡しました = gave/handed a business card

With 渡す, the usual pattern is:

• someone に something を 渡す

For example:

• 友だちに本を渡す = give a book to a friend
• 先生にレポートを渡す = hand a report to the teacher

In your sentence:

• お客様に = to the customer
• 私の名刺を = my business card
• 渡しました = gave/handed

渡しました is the polite past form of 渡す.

• dictionary form: 渡す = to hand over / to give
• polite non-past: 渡します
• polite past: 渡しました

So 渡しました means:

• handed over
• gave
• presented

In this context, handed or gave is natural, and because it is a business card, presented may also fit depending on the translation.

It is polite because of -ます, and past because of -ました.

Because 渡す focuses on the physical act of handing something over.

A business card is usually physically passed from one person to another, so 渡す is very natural.

By contrast:

• あげる means to give, but it is more general and less specifically about physically handing something over

In business-card situations, 名刺を渡す is the standard expression.

So:

• 名刺を渡しました sounds natural and idiomatic
• 名刺をあげました would sound less natural in this context

Japanese often omits the topic if it is already understood.

So even without 私は, the sentence can still mean:

• I gave my business card to the customer before the meeting

If you want to make the subject/topic explicit, you could say:

• 私は会議の前に、お客様に私の名刺を渡しました。

That would put more focus on I as the topic.

Japanese sentences very often leave out:

• the subject
• the topic
• even objects

when the context is clear.

Not completely. Japanese word order is more flexible than English, as long as the particles make the roles clear.

The original sentence is:

• 会議の前に、お客様に私の名刺を渡しました。

You could also see:

• お客様に、会議の前に、私の名刺を渡しました。
• 私は会議の前に、お客様に名刺を渡しました。

These all remain understandable because the particles show what each phrase is doing:

• に = time point / recipient
• を = direct object

However, the most natural order usually puts time expressions earlier and keeps the verb at the end.

Normally, no. With 渡す, the recipient is usually marked with に.

• お客様に名刺を渡しました = natural
• お客様へ名刺を渡しました = not the normal choice here

The particle へ mainly emphasizes direction toward a place or destination, while に is the normal marker for the recipient of giving.

So for a pattern like someone gives something to someone, use:

• A は B に C を 渡す

It is usually general: before the meeting.

By itself, 会議の前に does not specify exactly how long before:

• 5 minutes before
• 30 minutes before
• earlier that day

The exact timing depends on context.

If you wanted to be more specific, Japanese could add details such as:

• 会議の直前に = right before the meeting
• 会議の30分前に = 30 minutes before the meeting

So 会議の前に simply tells you the action happened earlier than the meeting.