qiūtiān de zhōumò, tā bú shì qù gōngyuán sànbù, jiù shì qù kāfēiguǎn kànshū.

的 links a modifier to a noun.

Here, 秋天 modifies 周末, so 秋天的周末 means the weekends in autumn or autumn weekends.

A natural way to think about it is:

• 秋天 = autumn
• 周末 = weekend
• 秋天的周末 = autumn’s weekends / weekends of autumn

In English, we often turn a noun into an adjective, as in autumn weekends. Chinese usually uses 的 to make that relationship clear.

Chinese usually puts time expressions before the main action, often near the beginning of the sentence.

So this pattern is very common:

• 时间 + 主语 + 动作
• On autumn weekends, she...

That is why 秋天的周末 comes before 她.

You could also say:

• 她秋天的周末不是去公园散步，就是去咖啡馆看书。

But putting the time phrase first is very natural, especially when setting the scene.

With time expressions, Chinese often omits 在 when the meaning is already clear.

So both of these are possible:

• 秋天的周末，她...
• 在秋天的周末，她...

The version without 在 is very natural and common. Adding 在 is not wrong, but it can sound slightly more explicit or heavier than necessary.

This is similar to how Chinese often says:

• 今天我很忙 = I am busy today

instead of needing something like 在今天.

This is because of tone sandhi.

不 is normally fourth tone: bù. But when it comes before another fourth-tone syllable, it changes to second tone: bú.

Since 是 is fourth tone, 不是 is pronounced:

• bú shì

The character stays the same, but the pronunciation changes.

不是...就是... is a fixed pattern meaning either...or...

So:

• 不是去公园散步，就是去咖啡馆看书
• Either she goes to the park for a walk, or she goes to a café to read

Very important: the first 不是 here is not being used as a simple negative in the usual sense of is not. The whole pattern works together as one structure.

So you should learn it as a chunk:

• 不是 A，就是 B = either A, or B

Normally it means one or the other, not both at once.

In this sentence, the idea is that on autumn weekends, her usual choice is limited to these two activities:

• go to the park for a walk
• go to a café to read

It gives a feeling like it is always one of these two.

In real life, context always matters, but the normal reading is either this or that.

Chinese often omits repeated subjects when they are already clear.

So after 她 is introduced once, it is understood that both options belong to her:

• 她不是去公园散步，就是去咖啡馆看书。

You do not need to say:

• 她不是去公园散步，就是她去咖啡馆看书。

That would sound unnecessarily repetitive.

It is repeated because each side of 不是...就是... is a full parallel option:

• 去公园散步
• 去咖啡馆看书

Repeating 去 makes the structure balanced and clear.

In English, we sometimes avoid repetition, but in Chinese, repeating the verb in matched structures often sounds more natural. It helps the listener immediately hear the two alternatives as separate but parallel choices.

These are very common Chinese action patterns:

• 去 + place + verb

So:

• 去公园散步 = go to the park and take a walk / go to the park for a walk
• 去咖啡馆看书 = go to a café and read

Chinese does not need extra words like to or in order to here. The destination comes first, and the activity after it.

Also:

• 散步 = to take a walk
• 看书 = to read books / do some reading

Both are very natural everyday expressions.

Chinese nouns usually do not change form for singular and plural, so 周末 can mean:

• the weekend
• weekends

Context tells you which one is meant.

Here, because the sentence describes a repeated habit and uses 秋天的周末, it means on autumn weekends in general.

If you wanted one specific weekend, you would usually say something clearer, such as:

• 这个周末 = this weekend
• 上个周末 = last weekend
• 那个周末 = that weekend

Yes. The comma helps separate the time-setting part from the main statement.

So the sentence is organized like this:

• 秋天的周末， = on autumn weekends
• 她不是...就是... = she either...or...

In writing, this comma makes the sentence easier to read. It is especially common when a time phrase or topic appears at the beginning of a sentence.