tā dìyīcì yí gè rén qù lǚyóu de shíhou, xīnli hěn jǐnzhāng, kěshì zuìhòu yíqiè dōu hěn shùnlì.

A natural way to divide it is:

她第一次一个人去旅游的时候， = When she traveled alone for the first time,

心里很紧张， = she felt nervous inside / in her heart

可是最后一切都很顺利。 = but in the end everything went smoothly.

So the overall pattern is:

[time clause] + [main statement] + [contrast] + [result]

More literally:

• 她 = she
• 第一次一个人去旅游的时候 = at the time when she traveled alone for the first time
• 心里很紧张 = felt very nervous inwardly
• 可是最后一切都很顺利 = but in the end everything was smooth

第一次 means the first time.

It is made of:

• 第 = ordinal marker, like -th in English
• 一 = one
• 次 = measure word for occurrences or times

So:

• 一次 = one time / once
• 第一次 = the first time

次 is used because this is about how many times something happened, not counting physical objects.

This is a very common tone change rule.

Normally 一 is first tone: yī.
But in actual speech, it changes depending on the next syllable:

• before a 4th tone, 一 becomes yí
• before a 1st, 2nd, or 3rd tone, it usually becomes yì
• when said alone or emphasized, it stays yī

So here:

• 一个: 个 gè is 4th tone, so 一 becomes yí
• 一切: 切 qiè is 4th tone, so 一 becomes yí

That is why you see yí gè and yíqiè.

It can mean both, depending on context.

Here, 一个人去旅游 means to travel alone / by oneself.

So although the literal meaning is one person, in many sentences it works like alone:

• 我一个人住。 = I live alone.
• 她一个人去。 = She goes by herself.

In this sentence, it does not just mean that there was one person in some abstract sense. It specifically describes her doing the trip on her own.

Yes. Mandarin often uses this pattern:

第一次 + verb phrase = the first time doing something

So:

• 第一次去中国 = the first time going to China
• 第一次开车 = the first time driving
• 第一次一个人去旅游 = the first time traveling alone

This is very natural Chinese word order.
The idea is that 第一次 comes before the action it refers to.

In this sentence, that whole chunk is then followed by 的时候:

第一次一个人去旅游的时候 = when she traveled alone for the first time

的时候 means when or at the time when.

It is attached to a phrase or clause to make a time expression:

• 我小时候 = when I was little
• 吃饭的时候 = when eating / during mealtime
• 下雨的时候 = when it rains

So here:

第一次一个人去旅游的时候 = when she traveled alone for the first time

A useful pattern is:

[clause] + 的时候 = when [clause happens]

Yes, it is the same written character 的, but here it is part of a fixed time expression pattern.

In beginner terms, you can treat:

[clause] + 的时候 as a set meaning when...

So you do not need to over-analyze it every time.
For learners, it is usually best to memorize 的时候 as a common grammar structure.

Examples:

• 我来的时候 = when I came
• 她睡觉的时候 = when she is sleeping
• 第一次见他的时候 = when I met him for the first time

Both can be natural, but they feel slightly different.

• 旅游 can itself mean to travel / to go sightseeing
• 去旅游 literally adds go, so it feels like go traveling

So:

• 她第一次一个人旅游 = She traveled alone for the first time.
• 她第一次一个人去旅游 = She went traveling alone for the first time.

Adding 去 often makes the action feel a bit more concrete or directional, especially when talking about setting out on a trip.

Both are possible, but 心里 adds an inner, emotional nuance.

• 她很紧张 = She was nervous.
• 她心里很紧张 = She felt nervous inside / in her heart

心里 literally means in the heart, but in natural English it often corresponds to:

• inwardly
• inside
• in her heart
• mentally / emotionally

So this version emphasizes her internal feeling, not just her outward state.

This is an extremely common Mandarin question.

In Chinese, adjectives can act as predicates, but they often sound more natural with 很 in a simple statement.

So:

• 她很紧张
• 一切都很顺利

are very normal.

Here, 很 does not always have to mean a strongly emphasized very. Sometimes it mainly helps the sentence sound complete and natural.

So these can be understood as:

• 心里很紧张 = felt nervous / was quite nervous
• 一切都很顺利 = everything went smoothly / was quite smooth

If you want stronger emphasis, you could use words like:

• 非常
• 特别
• 十分

可是 means but / however.

In this sentence, it introduces a contrast:

• she was nervous at first
• but in the end, everything went smoothly

可是 and 但是 are very similar, and in many cases they are interchangeable.

Very roughly:

• 可是 can feel a little more conversational
• 但是 can feel a little more neutral or formal

So this sentence could also use 但是 without changing the basic meaning.

Here 最后 means in the end / finally / eventually.

It does not mean last in the sense of the last one here.
Instead, it marks the final outcome of the situation.

So:

可是最后一切都很顺利 = but in the end everything went smoothly

It is pointing to the result after the earlier nervousness.

都 often marks the idea of all.

Since 一切 means everything, Chinese commonly uses 都 with it:

• 大家都来了 = Everyone came.
• 东西都准备好了 = The things are all ready.
• 一切都很顺利 = Everything went smoothly.

Even though 一切 already has an all/everything meaning, adding 都 is still very natural and standard in Chinese.

In Mandarin, adjectives can directly function as predicates.

So:

• 她很紧张 = She was nervous.
• 事情很顺利 = The matter went smoothly / was smooth.

Because of that, Chinese does not need 是 here.

In fact, 是 would usually be wrong in this kind of sentence:

• 一切都很顺利 = correct
• 一切都是很顺利 = unnatural in this context

Also, in English 顺利 often gets translated more adverbially:

• went smoothly
• was smooth / successful

But in Chinese it is functioning as an adjective.

Not exactly.

顺利 means smooth, without major problems, or successful in proceeding as expected.

So 一切都很顺利 means:

• everything went smoothly
• everything proceeded without problems
• things turned out well

It does not necessarily mean the trip was easy or effortless.
It mainly means there were no serious difficulties and things worked out well.

Yes. Chinese allows several natural variations. For example:

• 她第一次一个人去旅游的时候，很紧张，可是最后一切都很顺利。
• 她第一次一个人去旅游时，心里很紧张，可是最后一切都很顺利。

These mean almost the same thing.

Changes like this are common:

• 的时候 → 时: more concise, a bit more written
• removing 心里: less emphasis on inner feeling

The original sentence sounds natural and expressive because 心里 highlights her internal nervousness.