jihacheoreseo jongichaekboda jeonjachaegeul deo jaju ilgda boni yejeonboda chaegeul deo manhi ilgge dwaesseo.

에서 marks the place where an action happens. Since 읽다 is an action, 지하철에서 means on the subway / in the subway as the location where the reading happens.

Compare:

• 지하철에 = to the subway / on the subway / at the subway, depending on context
• 지하철에서 읽다 = read on the subway

So here, 에서 is the natural choice because the sentence is talking about the place where the speaker reads.

This part uses the comparison pattern:

• A보다 B를 더 + verb = do the verb with B more than with A

So:

• 종이책보다 = than paper books
• 전자책을 더 자주 읽다 = read e-books more often

Together, it means:

• to read e-books more often than paper books

A learner might expect something like 전자책을 종이책보다 더 자주 읽다, and that is also perfectly normal. Korean word order is flexible here as long as the particles make the roles clear.

Because the sentence makes two different comparisons:

1. 종이책보다 전자책을 더 자주 읽다 → comparing paper books and e-books

2. 예전보다 책을 더 많이 읽게 됐어 → comparing now and before

So the first 보다 compares what kind of book is read more often, and the second 보다 compares time.

They describe different kinds of increase:

• 더 자주 읽다 = read more often
  → frequency goes up

• 더 많이 읽다 = read more
  → amount goes up

In this sentence, the idea is:

• I read e-books more often than paper books
• and as a result, I ended up reading more books than before

So 자주 is about how often the action happens, while 많이 is about the quantity.

-다 보니 means something like:

• while doing
• after doing something repeatedly / continuously
• as I kept doing it, I realized / it turned out that...

So 읽다 보니 is not just a plain sequence like and then. It suggests that through the repeated habit of reading e-books on the subway, a certain result happened naturally.

In this sentence:

• 전자책을 더 자주 읽다 보니 = As I kept reading e-books more often... = After finding myself reading e-books more often...

It introduces the cause or background for the result in the second half.

Both can connect cause and result, but -다 보니 has a more experiential or gradual feeling.

• -아서/어서 = straightforward cause/result

  • 비가 와서 집에 있었어
    = It rained, so I stayed home.

• -다 보니 = something became clear or happened as a result of repeatedly doing something

  • 한국어를 공부하다 보니 재미있어졌어
    = As I kept studying Korean, it became fun.

In your sentence, 읽다 보니 sounds natural because the result came from an ongoing habit, not just one simple cause.

-게 되다 means to come to, to end up, or to start being in a situation where...

So:

• 책을 더 많이 읽었어 = I read more books
• 책을 더 많이 읽게 됐어 = I ended up reading more books / I came to read more books

The second one emphasizes a change of habit or situation. It suggests that because of reading e-books more often on the subway, the speaker's reading habit changed.

So 읽게 됐어 is a better fit than 읽었어 because the sentence is about how one behavior led to a new pattern.

They mean the same thing. 됐어 is just the contracted form of 되었어.

• 읽게 되었어 = more complete/full form
• 읽게 됐어 = shortened, very common in speech and casual writing

Native speakers use the contracted form a lot, so 읽게 됐어 sounds very natural in conversation.

Because -어/아 style is casual speech.

• 됐어 = casual
• 됐어요 = polite
• 되었습니다 / 됐습니다 = formal

So this sentence sounds like something you would say to a friend or someone you speak casually with.

A polite version would be:

• 지하철에서 종이책보다 전자책을 더 자주 읽다 보니 예전보다 책을 더 많이 읽게 됐어요.

Because the meaning becomes broader in the second half.

The first half is specifically about e-books vs paper books:

• 종이책보다 전자책을 더 자주 읽다 보니

But the result is about reading books in general more than before:

• 예전보다 책을 더 많이 읽게 됐어

This suggests that reading e-books more often increased the speaker’s overall reading amount, not just the amount of e-books.

Yes, basically. 예전 means the past / earlier times / before, and 보다 means than.

So:

• 예전보다 = than before / compared to before

It is a very common expression when talking about change over time.

Examples:

• 예전보다 바빠졌어.
  = I’ve become busier than before.
• 예전보다 한국어를 잘해.
  = I’m better at Korean than before.

Yes. Korean often omits the subject when it is clear from context.

This sentence does not explicitly say I, but because of the casual ending 됐어 and the personal, experiential content, the implied subject is naturally I.

So the full implied meaning is something like:

• I read e-books more often than paper books on the subway, and as a result I’ve come to read more books than before.

Omitting the subject makes the sentence sound natural and normal in Korean.

Usually, in this kind of sentence, people will understand it as on the subway or while riding the subway.

Technically, 지하철 can refer to the subway system in general, and context matters. But because the action is reading, the natural interpretation is that the speaker reads during subway rides.

If someone wanted to be very specific about at the station, they might say something like:

• 지하철역에서 = at the subway station

So here, 지하철에서 is most naturally understood as on the subway.

종이책 literally means paper book, so it is used to contrast with 전자책.

Without that contrast, people would often just say 책. But once 전자책 appears, 종이책 becomes useful because it clearly means a physical, printed book.

So:

• 책 = book(s) in general
• 종이책 = physical/paper book(s)
• 전자책 = e-book(s)

Using 종이책 here makes the comparison explicit and natural.