Tā xiàwǔ yào qù yóujú jì dōngxi, yě shùnbiàn bāng wǒ qiānshōu nàge kuàidì.

In Chinese, a common word order is:

Subject + time + modal/auxiliary + verb phrase

So:

她 下午 要 去邮局寄东西
= She / in the afternoon / is going to / go to the post office to mail something

Putting the time word after the subject is very natural in Mandarin. English often puts time at the end, but Chinese often places it earlier.

Here, 要 means something like be going to, intend to, or will.

So 下午要去 means:

• will go in the afternoon
• is going to go in the afternoon
• plans to go in the afternoon

It does not mean want here in the strongest sense.
Chinese 要 can mean different things depending on context:

• 我要咖啡。 = I want coffee.
• 我要去邮局。 = I’m going to the post office / I plan to go to the post office.

去 means to go. In Chinese, if someone is going somewhere in order to do something, it is very common to say:

去 + place + verb

So:

去邮局寄东西
literally = go to the post office mail things

In natural English, that becomes go to the post office to mail something.

Chinese often uses a series of verbs like this without needing a separate word for to.

Chinese often links actions directly in sequence. This is sometimes called a serial verb construction.

So:

去邮局寄东西
is literally more like:

• go to the post office
• mail things

The relationship between the actions is understood from the order. The first action sets up the second one.

English usually needs to:
go to the post office to mail something

Chinese does not need an extra word there.

Yes. 东西 literally means thing(s), stuff.

So 寄东西 literally means send/mail things.

In real usage, it can refer to:

• a package
• documents
• some items
• something unspecified

Chinese often uses broad words like 东西 when the exact object is not important.

Because 东西 here is being used in a general, non-counted way, similar to stuff or things in English.

If you wanted to count specific items, you would usually need a measure word, for example:

• 寄一个东西 = mail one item
• 寄两件东西 = mail two items

But in 寄东西, it just means mail something / mail some things, so no measure word is needed.

The comma separates two related actions done by the same person:

1. 下午要去邮局寄东西
2. 也顺便帮我签收那个快递

The subject 她 is understood to continue into the second part, so Chinese often leaves it out to avoid repetition.

So the second clause is understood as:

她也顺便帮我签收那个快递

Omitting repeated subjects is very common in Chinese when the meaning is clear.

也 means also or too.

Here it shows that, in addition to mailing something, she will also do another action: sign for the delivery for me.

So:

也顺便帮我签收那个快递
= also, while she’s at it, help me sign for that delivery

As for placement, 也 usually comes before the verb phrase or before the part it modifies. In this sentence, it comes before 顺便帮我签收..., meaning the whole second action is an additional one.

顺便 means:

• conveniently
• while one is at it
• on the way
• in passing

It describes doing something extra without making a separate special trip.

So 也顺便帮我签收那个快递 means something like:

• she’ll also, while she’s there, help me sign for that package
• she’ll also do that for me at the same time

It often appears before the verb:

• 顺便买一下 = buy it while you’re at it
• 顺便问一下 = ask while you’re at it

This pattern is very common:

帮 + person + verb

So:

帮我签收
= help me sign for it
or more naturally
= sign for it on my behalf

Here, 我 is the person receiving the help, and 签收 is the action being done.

Other examples:

• 帮我买一下。 = Help me buy it.
• 帮她看看。 = Help her take a look.
• 帮我们订票。 = Help us book the tickets.

签收 means to sign for and receive something, especially a delivery, package, or official item.

It combines the ideas of:

• 签 = sign
• 收 = receive

So it is not just receive in a general sense. It specifically implies confirming receipt, usually by signing or formally accepting it.

That is why it fits well with 快递.

Yes. In 那个快递, the 个 is functioning as the measure word.

This is the structure:

那 + 个 + 快递
= that + classifier + delivery/package

So 那个快递 means that package / that delivery.

For English speakers, it may look like one word, but it is really:

• 那 = that
• 个 = classifier
• 快递 = express delivery / package

In casual modern Chinese, 个 is used very widely, even when another classifier might also be possible.

It can mean either one depending on context.

Common meanings of 快递 include:

• express delivery
• courier service
• the delivered package itself

In this sentence, 签收那个快递 most naturally means sign for that package/delivery.

So here it refers to the item being delivered, not the company.

Because 那个 is directly modifying the noun 快递.

This is just a normal demonstrative phrase:

那个快递 = that package

You do not need 的 between a demonstrative-classifier phrase and the noun.

Compare:

• 这个人 = this person
• 那本书 = that book
• 那个快递 = that package

Using 的 here would sound wrong.

Sometimes yes, but the nuance is a little different.

• 帮我签收 emphasizes helping me by doing it for me.
• 给我签收 can sound like sign for it for me, focusing more on the action being done on my behalf.

In many everyday situations, 帮我签收 is the most natural and clear choice.

You may also hear:

• 替我签收 = sign for it on my behalf

That one is also very natural and slightly more explicit.

Because the second syllable is usually in the neutral tone.

So:

• 东 = first tone
• 西 in 东西 becomes a neutral-tone xi

This is very common in everyday speech. Many two-syllable words in Mandarin have an unstressed second syllable.

So the pronunciation is closer to:

dōngxi

not a fully stressed dōngxī.

Good question. In careful pronunciation, 那个 is often given as nàge.

But in natural speech, many speakers pronounce it closer to:

nèige

This is very common in conversation.

So:

• textbook / citation form: nàge
• common spoken form: nèige

Both refer to the same word here: that.

It has two connected actions:

1. 她下午要去邮局寄东西
2. 也顺便帮我签收那个快递

They are linked because they happen in the same general outing or situation.

So the whole sentence means that she has one main plan, and then one additional convenient action.

This kind of chaining is very natural in Chinese and helps sentences sound compact and smooth.