Difference between 建てられた and 建てました?

Question

新しい大学のビルが建てられた。

新しい大学のビルを建てました。

Both translate to: A new university building was built.

Even though the translation is the same (by my understanding) something to do with the meaning has to be different. I know the first sentence is passive form, the other you're everyday form (sorry, don't know what its proper name is) but I can't figure out what the difference is. I'm sure the different particles of が and を have something to do with it.

Answer 1

It's a little bit of an apples-to-oranges comparison:

   建てられた　　　＝　　建てる　＋　られる　　　　　　＋　た    (passive +          past)  
   建てました　　　＝　　建てる　＋　　　　　　　ます　＋　た    (          polite + past)

One verb has the polite auxiliary 〜ます, the other has the passive auxiliary 〜られる. Both verbs have the past auxiliary 〜た. But these are all separate variables, and we can use any combination of them:

   建てる　　　　　＝　　建てる　＋　　　　　　　　　　　　　    (                       )
   建てた　　　　　＝　　建てる　＋　　　　　　　　　　＋　た    (                   past)
   建てます　　　　＝　　建てる　＋　　　　　　　ます　　　　    (          polite       )
   建てました　　　＝　　建てる　＋　　　　　　　ます　＋　た    (          polite + past)
   建てられる　　　＝　　建てる　＋　られる　　　　　　　　　    (passive                )
   建てられた　　　＝　　建てる　＋　られる　　　　　　＋　た    (passive          + past)
   建てられます　　＝　　建てる　＋　られる　＋　ます　　　　    (passive + polite       )
   建てられました　＝　　建てる　＋　られる　＋　ます　＋　た    (passive + polite + past)

But I think we can set aside the polite and past auxiliaries and just compare passive to active.

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Forming the passive

Let's start with a basic active sentence:

新しい大学のビルを建てた。

Like many Japanese sentences, this one doesn't have an explicit subject. That's fine, of course, but it'll be easier to talk about the passive here if we put one in. We won't worry here about whether it's natural to do so or whether we should use は. I'll just add 私が to the sentence:

私が新しい大学のビルを建てた。
I built a new university building.

We can make this into a direct passive with three steps:

1. Add 〜られる.

   　　　　　　　　　　　　私が　　新しい大学のビルを　　建てられた。

2. Replace が with に, and replace を with が.

   　　　　　　　　　　　　私に　　新しい大学のビルが　　建てられた。

3. Move the が-phrase before the に-phrase.

   　新しい大学のビルが　　私に　　　　　　　　　　　　　建てられた。

   (Japanese word order is flexible and the が-phrase doesn't have to come before the に-phrase, but I include this step because I think it's the most basic word order for a direct passive.)

Now we've got a passive sentence:

新しい大学のビルが私に建てられた。
A new university building was built by me.

In this sentence, just like in its English translation, the building is the subject. (In Japanese the subject is marked with が, while in English it's marked by its position at the beginning of the sentence.) The person who built it isn't the subject anymore—they now appear as 私に "by me", a phrase that appears later in the sentence.

Of course, you might think "by me" sounds a little silly in English. That's true, and most often we'd leave it out in English. We can remove 私に in Japanese, too, but unlike in English we can also remove 私が from the active version.

Let's remove 私 from both versions:

新しい大学のビルが建てられた。
A new university building was built. (passive)

新しい大学のビルを建てた。
[I] built a new university building. (active)

And now we have sentences like yours. Hopefully you can see the difference :-)

Answer 2

Answer

Completely different.

Reason

First one's meaning is as same as you said.

But second one, [新]{あたら}しい[大学]{だいがく}のビルを[建]{た}てました doesn't mean same.

The point is a verb 建てる (build/construct).

First one, 建て|られ|た is a passive and past tense form of 建てる. The section られ expresses the passive form and た expresses past tense. So, it can be translated in English like:

新しい大学のビルが建てられた。 -> A new university building was built.

Why the second one doesn't have same meaning is, because 建てました is a normal, past tense, and polite language form.

Thus, the second one can be translated like:

新しい大学のビルを建てました。 -> I built a university building.

Reference

Polite language, [敬語]{けいご}, is an expression of a respect for the person you're talking to. There are some group of Keigo; [丁寧語]{ていねいご}, [尊敬語]{そんけいご}, and [謙譲語]{けんじょうご}.

In this case, 建てました belongs to [丁寧語]{ていねいご}. If you want to speak the second sentence in normal language, it will be like:

新しい大学のビルを建てた。

Answer 3

This first sentence is in the passive voice, while the second sentence is in the active voice. Direct translations of each:

• A new university building was built.
• [Someone unspecified] built a new university building.

Japanese often omits the subject of the sentence if that subject can be understood from context, such as if the subject were already established earlier in the conversation or text.

The two clues about passive vs. active are 1) particles, and 2) verb conjugations. Chopping the sample sentences down to the bare bones for demonstration, let's use the following:

• ビルが建てられた。
• ビルを建てた。

Particles

The two particles in our samples are が, indicating the subject of the verb, and を, indicating the object of the verb.

In the first sentence, ビル is followed immediately by が, telling us that this is the subject -- the building is the one doing the action. From an English speaker's perspective, this might seem odd: buildings don't do much but sit there. But in both Japanese and English, in the passive voice, the person or thing being done to by the action of the verb is also the subject of the verb phrase: in an apple is eaten or the bone is chewed, both "apple" and "bone" are the subjects of the verb phrases.

In the second sentence, ビル is followed immediately by を, telling us that this is the object -- someone else is doing the action to the building. This is more straightforward from an English speaker's perspective: in I eat an apple or the dog chews a bone, both "apple" and "bone" are the objects of the verb action.

Verb Conjugations

Japanese verbs change in various ways depending on the social context (who is talking, who is listening, who is being talked about), time (when the action happens relative to the time frame of the context, kinda like tense, but different -- this is called aspect), and voice or valency (things like passive, active, causative). Here, we're only looking at the last bit.

In 建てられた, there's that extra られ that tells us that this verb is in the passive conjugation. See the Wikipedia article on Japanese verb conjugations for more.