kanozyo ha ame ni nureta kami wo hankati de hukinagara, waratte ita.

は marks 彼女 as the topic: we are talking about her and then describing what she was doing.

• 彼女は... = As for her...
• 彼女が... would put more focus on she as the one doing it, often with a contrast like she, not someone else

In this sentence, は sounds natural because it feels like part of a scene or description.

With ぬれる meaning to get wet, Japanese often uses に for the thing that causes the wetness.

• 雨にぬれる = get wet in the rain / be soaked by rain
• 水にぬれる = get wet with water

So 雨にぬれた髪 means hair that got wet from the rain.

For this verb, に is very common and natural. It does not mean an indirect object here.

Because ぬれた is inside a noun-modifying clause.

• 雨にぬれた髪 = hair that got wet in the rain / rain-wet hair

The past form here does not simply mean the whole sentence is finished. It shows that the hair became wet before or by the time she was wiping it.

So the sequence is roughly:

1. the hair got wet
2. she was wiping it
3. she was smiling

It is one noun phrase:

• 雨にぬれた = got wet in the rain
• 髪 = hair

Japanese puts modifiers before the noun, so:

• 雨にぬれた髪 = rain-soaked hair / hair that was wet from the rain

This is the same pattern as:

• 昨日買った本 = the book I bought yesterday
• よく知られている店 = a well-known shop

Because 髪 is the direct object of ふく.

• ふく = to wipe
• 髪をふく = wipe one’s hair

More precisely, the whole object is:

• 雨にぬれた髪を = her rain-wet hair

So を marks what she was wiping.

Because Japanese often leaves out possession when it is obvious from context.

Since 彼女 is the subject and no other person is mentioned, 髪 is naturally understood as her hair.

So:

• 彼女は髪をふいた usually means She wiped her hair
• You only need 彼女の髪 if you want to be especially clear or contrast it with someone else’s hair

で marks the tool or means used to do something.

• ハンカチでふく = wipe with a handkerchief

Other examples:

• 箸で食べる = eat with chopsticks
• ペンで書く = write with a pen

So ハンカチで tells us what she used to wipe her hair.

Verb stem + ながら means while doing...

• ふく → stem ふき
• ふきながら = while wiping

Important points:

1. The two actions usually happen at the same time.
2. The subject is normally the same for both actions.

So here, she is both:

• wiping her hair
• smiling

The main action is the verb at the end: 笑っていた.

The ながら part is subordinate:

• ふきながら = while wiping
• 笑っていた = was smiling

So the sentence is structured like:

• While wiping her rain-wet hair with a handkerchief, she was smiling.

Japanese often puts the background or accompanying action in the ながら clause and the main description at the end.

笑っていた is the past form of ている, which often shows an ongoing action or state in the past.

So:

• 笑った = smiled / laughed
• 笑っていた = was smiling / kept smiling

In this scene, 笑っていた gives a softer, more continuous, descriptive feeling. It paints a picture of her expression during the action.

If you used 笑った, it would sound more like a single completed event: she smiled.

Yes, to some extent. Because Japanese uses particles like は, を, and で, the grammatical roles stay clear even if some parts move.

For example, this is also natural:

• 彼女はハンカチで雨にぬれた髪をふきながら、笑っていた。

The meaning stays basically the same. The original sentence is fine, but Japanese allows more flexibility than English.

No. Normal Japanese is usually written without spaces between words.

So this sentence would normally appear as:

• 彼女は雨にぬれた髪をハンカチでふきながら、笑っていた。

The spaces in your version are just for learners, to make the parts easier to see.