kanozyo ha ase wo hukinagara, kokage no benti ni suwatta.

は marks 彼女 as the topic: as for her.... That is natural when the person is already known from context, or when the speaker is simply talking about what she did.

If you used が instead, it would sound more like:

• identifying her as the subject
• emphasizing that she is the one who did it
• introducing her more newly into the scene

So 彼女は is a very normal narrative choice.

Because ふく is a transitive verb here, and 汗 is its direct object.

So:

• 汗をふく = to wipe sweat
• literally, wipe the sweat

English often says wipe sweat from your face, but Japanese commonly just marks sweat itself with を.

It is:

• ふく → verb stem ふき
• ふき + ながら

The pattern verb stem + ながら means while doing ...

So ふきながら means:

• while wiping
• here, specifically while wiping sweat

It connects two actions done by the same person at roughly the same time.

Yes, in normal Japanese, ながら usually assumes the same subject for both actions.

So in this sentence:

• she wiped sweat
• she sat on the bench

Both actions are understood to be done by her.

That is one of the key things to remember about ながら.

With ながら, the tense is usually shown on the main verb, not on the ながら part.

So:

• ふきながら、座った = while wiping, she sat down
• the whole sentence is past because 座った is past

This is normal Japanese grammar. The ながら clause itself does not separately show past tense here.

Because 座る normally goes with に.

Here, に marks the place/surface where someone ends up sitting:

• 椅子に座る = sit on a chair
• 床に座る = sit on the floor
• ベンチに座る = sit on a bench

Using で would sound unnatural here. で marks the place where an action happens, but 座る is commonly treated as moving into a seated position, so に is the standard particle.

木陰 is read こかげ.

It means:

• the shade of a tree
• tree shade
• sometimes more generally a shady spot under trees

It is a common compound noun. You may also see expressions like 木の陰, but 木陰 is the compact, set word.

Here, の links two nouns, with the first noun describing the second.

So 木陰のベンチ means something like:

• the bench in the shade of a tree
• the bench under the tree shade
• the shaded bench under the trees

This の does not have to mean ownership. It can also show location, type, category, or description.

Yes. It could be written as 拭きながら.

Japanese often writes this verb in hiragana as ふく / ふき because:

• the kanji 拭 is relatively less common and a bit harder
• hiragana often looks more natural in everyday writing
• context makes the meaning clear anyway

So both are possible:

• 汗をふきながら
• 汗を拭きながら

By itself, 座った most naturally means sat down or sat as an action.

In this sentence, that is probably the best understanding:

• she wiped sweat
• and sat down on the bench

If you wanted to clearly express the ongoing state was sitting, Japanese would more often use something like:

• 座っていた

So 座った here is best understood as the event of taking a seat.

Yes, 彼女 can mean either:

• she
• girlfriend

In this sentence, it is most naturally understood as she, because it is being used as the topic of a narration.

Still, outside context, 彼女 can be ambiguous. Japanese also often omits pronouns entirely when the subject is already clear, so a real-life sentence might simply leave 彼女 out.

Yes, it can.

The comma is not strictly required, but it is very natural because the ながら phrase comes before the main action and the comma helps show a pause:

• 彼女は汗をふきながら木陰のベンチに座った。
• 彼女は汗をふきながら、木陰のベンチに座った。

Both are fine. The version with the comma is a little easier to read.

It could definitely be omitted if the context already makes the subject clear.

Japanese often leaves out subjects when they are understood. So in a story, after she has already been mentioned, you might simply get:

• 汗をふきながら、木陰のベンチに座った。

That would still naturally mean she sat down on the bench in the shade while wiping sweat, if the context already tells us who she is.