Learn Hardcore Chinese: tā mǎi le yìshuāng xīn yùndòngxié, shuō zài gōngyuán pǎobù de shíhou bǐ chuān píngshí de xiézi shūfu duō. - She bought a pair of new sneakers, saying that running in the park in them is much more comfortable than wearing her usual shoes.

她买了一双新运动鞋 = She bought a pair of new sports shoes (the buying is completed).
Without 了: 她买一双新运动鞋 sounds like a plan or a general statement (e.g., on a shopping list), not a specific completed purchase.

Chinese doesn’t have grammatical tense like English; time is expressed through context, time words (昨天, 明天, etc.), and aspect markers like 了, 过, 在. Here, 了 simply tells us the buying is done.

Why do we say 一双新运动鞋 and not something like 两个新运动鞋 or 两只新运动鞋?

For shoes, the standard measure word is 双 (pair):

一双鞋 – a pair of shoes
两双鞋 – two pairs of shoes

Using 两个 or 两只 with 鞋 would sound unnatural in normal conversation unless you are talking about individual shoes for some special reason (e.g., a one‑legged person or mismatched single shoes).

So 一双新运动鞋 is the natural way to say a pair of new sports shoes.

Why is it 新运动鞋 and not 运动新鞋? What’s the order between 新 and 运动鞋?

运动鞋 is a compound noun meaning sports shoes / sneakers. It’s treated like one word.

Then 新 is an adjective modifying 运动鞋:

新运动鞋 = new sports shoes (new sneakers)

This matches the usual pattern:

新衣服 – new clothes
新手机 – new cell phone

Putting 新 between 运动 and 鞋 (运动新鞋) would sound wrong; it would be like breaking the word 运动鞋 apart. You almost always keep 运动鞋 together and put adjectives like 新 in front of the whole noun.

In 说在公园跑步的时候, who is doing the running? Why is 她 missing?

The subject 她 is understood from context and can be dropped in Chinese once it’s clear.

The full “English‑style” structure would be:

她说她在公园跑步的时候…
She said that when she runs in the park…

But in Chinese it’s very common to omit the second 她:

她说在公园跑步的时候…

Listeners understand that the runner is still 她, because that’s the topic and no new subject was introduced. This dropping of repeated subjects is very natural in Chinese.

What is the role of 在 in 在公园跑步的时候? Could I say just 公园跑步的时候?

在 marks location (or sometimes “at / in / on” in general).

在公园 = in the park
在公园跑步 = run in the park

在公园跑步的时候 literally: at‑the‑park running de time → when (she) runs in the park.

If you drop 在 and just say 公园跑步的时候, it sounds incomplete or unnatural, because 公园 alone doesn’t function as a location phrase here without 在.

Why is there a 的 in 跑步的时候? What does 的时候 really mean?

的时候 means “when…” / “at the time when…”.

Structure:

[verb / verb phrase] + 的 + 时候
→ a time expression meaning “when doing X”.

Here:

跑步 – to run
跑步的 – “the (act of) running” (verb phrase nominalized by 的)
跑步的时候 – when (she is) running / the time of running

So the 的 here is a nominalizer: it turns the action 跑步 into something that can be treated like a “time” phrase together with 时候.

What does 比 do in 比穿平时的鞋子舒服多? How does the comparison work?

比 introduces a comparison: A 比 B + adjective (+ degree word) → A is (adjective)‑er than B.

In the sentence (filling in the implied subject):

(她说) 在公园跑步的时候
(她) 比穿平时的鞋子舒服多。

The pattern is:

(Using the new shoes) 比 (穿平时的鞋子) 舒服多。
= is much more comfortable than wearing her usual shoes.

More explicitly:

（穿新运动鞋）比（穿平时的鞋子）舒服多。
Wearing the new sneakers is much more comfortable than wearing her usual shoes.

So 比 introduces what you compare against; what comes before 比 (here understood from context) is what is “better / more …”.

Why is it 穿平时的鞋子 instead of 她平时穿的鞋子? Do they mean the same thing?

They’re similar in meaning but not identical in structure or nuance.

穿平时的鞋子
– literally: wear (her) usual shoes
– 平时的鞋子 = the shoes (she wears) normally / usually
– focus is on the type/category of shoes: her usual ones vs the new ones.
她平时穿的鞋子
– literally: the shoes that she normally wears
– 她平时穿的 modifies 鞋子, like a relative clause
– often feels a bit more descriptive or explicit, emphasizing the action habit (she normally wears them).

In this sentence, 穿平时的鞋子 is shorter and more natural, because the contrast is between 新运动鞋 and 平时的鞋子 as two categories.

What does 多 do in 舒服多? Is this the same as 舒服得多?

Here 多 is a degree intensifier in a comparison.

Pattern:

A 比 B + adjective + 多 / 得多
→ A is much more + adjective + than B

So:

舒服多 ≈ 舒服得多 ≈ much more comfortable.

Differences:

舒服多 – a bit more informal / colloquial; 多 directly follows the adjective.
舒服得多 – slightly more standard; 得多 is treated as one unit.

Both are common and grammatically correct. You cannot say 比…舒服很多? Actually you can:

比…舒服很多 – also OK, with 很多 as “a lot”, similar meaning.

Could we also say 舒服多了 here? What would 了 add?

Yes, you might see:

(比平时的鞋子) 舒服多了。

Adding 了 here often gives a sense of noticeable change / new state:

舒服多 – much more comfortable (degree)
舒服多了 – (has become) much more comfortable now or it’s way more comfortable (than before)

In spoken Chinese, 多了 after an adjective in a comparison is very common to emphasize a new, clearly different state: 好多了, 便宜多了, etc.

Can we drop 说 and just say: 她在公园跑步的时候比穿平时的鞋子舒服多?

You can drop 说 and get a grammatical sentence:

她在公园跑步的时候比穿平时的鞋子舒服多。

But:

With 说: the sentence is narration + reported comment:
She bought… and said that when she runs… it’s much more comfortable…
Without 说: it sounds like the narrator’s direct statement:
She bought… and when she runs… it’s much more comfortable… (said by the speaker, not necessarily by her).

So 说 tells us that the following comparison is her own comment, not the speaker’s independent observation.

Why do we need 的 in 平时的鞋子? Could we just say 平时鞋子?

的 connects modifiers to nouns. Here:

平时的鞋子 – the shoes (for) normal times / the shoes she usually wears
– 平时的 is an attributive phrase modifying 鞋子.

Without 的, 平时鞋子 sounds off; 平时 doesn’t naturally function as an adjective the way 新鞋子 does. You could say:

新鞋子 – new shoes (adjective + noun; no 的 needed)
平时穿的鞋子 – the shoes she normally wears (clause + 的 + noun)
平时的鞋子 – her usual / everyday shoes (time‑related phrase + 的 + noun)

So in 平时的鞋子, the 的 is required to make the phrase sound normal.

Is 时候 the same as 时间? Could we say 在公园跑步的时间 instead of 在公园跑步的时候?

They overlap in meaning but are not interchangeable in all structures.

时候 – “when / the time (that)”
- Very commonly used in time clauses: ……的时候, 小的时候, 来的时候, etc.
- Feels more like “at the point / period when something happens.”
时间 – “time” as a more general noun (amount of time, clock time, availability): 有时间, 很多时间, 没时间, etc.

In 在公园跑步的时候, 的时候 forms a “when‑clause”. Saying 在公园跑步的时间 would emphasize the duration / amount of time spent running in the park, not “when she runs in the park” as a condition for comparison. It would also make the structure after 说 rather clumsy.

So 在公园跑步的时候 is the natural, idiomatic choice for “when (she) runs in the park”.