Difference between 建てられた and 建てました?


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.




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

[code]

       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)
    
[/code]

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:

[code]

       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)
    
[/code]

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

* * *

## 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 :-)




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

[code]

       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)
    
[/code]

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:

[code]

       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)
    
[/code]

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

* * *

## 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 :-)

