However, since I dropped by a nearby convenience store this morning, I walked along theat street for about 20 meters this morning.

At first I was a bit confused, so I made two changes that can help. I moved "this morning" earlier because it helps to emphasise the idea that you did something different than normal this morning. Then I changed "the street" to "that street". This helps to emphasise that you didn't cross the aforementioned street with the tram but walked along it.

Looking more closely, it seemed she was eating something because her mouth was moving.

She was holding two things in her both hands, but they were not, but neither one looked like food.

Her mouth appeared to be moving, as if she was choewing something.

In traditional Japan, a woman (not only women but also men, of course) standing and eating something outside was considered rude and disgraceful.

No corrections, but this and the next two sentences are quite an abrupt aside. Normally there would be a transition like: This reminded me that traditionally...

And after the aside: my thoughts returned to the present when I saw ash he had stopped moving her mouth.

Maybe she had just swallowed her food and stopped chewing, or perhaps I had been mistaken and she wasn't eating her breakfast from the beginningafter all.

I needed to reassess ther situation.

It would only be "her" situation if from her perspective there was a situation. You're an observer so keeping it detached is more natural

From about 10 meters away, I focustried ton figuringe out what was going on.

This iwas another ordinary moment in my morning.

However, since I dropped by a nearby convenience store, I walked along theat street for about 20 meters this morning.

There was a tram stop, and a young woman, around 20 years old, was standing there.

Looking more closely, it seemed she was eating something becaussince her mouth was moving.

She was holding two things in her both hands, but they were notdidn't look like food.

Her mouth appeared to be moving, as if she was choewing something.

"chow" is a word, but in this case it's wrong to use.

In traditional Japan, a woman (not only women but also men, of coursewell not just women but men as well) standing and eating something outside was considered rude and disgraceful.

However, the younger generation would probably saychallenges this notion, thinking, "Why not?"

TShen s then stopped moving her mouth.

Maybe she had just swallowed her food and stopped chewing, or perhaps I had been mistaken and she wasn't eating her breakfast from the beginning.at all.

I needed to reassess ther situation.

This iwas another ordinary moment in my morning.

Looking more closely, it seemed she was eating something because her mouth was moving.

She was holding two things in her both of her hands, but they were not food.

Her mouth appeared to be moving, as if she was choewing something.

However, since I droppeding by a nearby convenience store, I walked along theat street for about 20 meters this morning.

There was a tram stop, and a young woman, who was around 20 years old, was standing there.

Looking more closely, it seemed she was eating something because her mouth was moving.

She was holding two things in her both of her hands, but they were not food.

In traditional Japan, a woman (not only women but also men, of course)it was considered rude and disgraceful to standing and eating some things outside was considered rude and disgraceful.,

IAt one time, that was seen as a breach of common courtesy.

Also, in Tokyo I often see young people doing this.

However, themany younger generationJapanese would probably say, "Why not?"

From about 10a ten meters away, I focused on figuring out what was going on.

In the end, it turned out that what she was holding in her right hand was a mobile fan.

This iwas another ordinary moment in my morning.