'私は学生です' & '夜に部屋では電気をつけない' : 'は'　'では'


I'm so confused about the sentence structure'...では...' we say '私は学生です' 'は'
here can mean 'be' but Japanese people would say '夜に部屋では電気をつけない' and
'その店では洋書が売られている' So the first sentence mean '(I) don't switch on the light in
(my) room at night' The particle 'で'serves as a preposition which has meaning
similar to 'in'. But what's the point in adding 'は' here?

Is it okay to elimiate 'は' from the sentence? Any changes in meaning when は or
で is included or exclused in the sentence??




Let me caveat this answer by saying that I've only been learning for a year
and use of は is a mind bending subject.

First of all, は does **not** mean 'be'. If you really think this then you have
a serious misunderstanding. In your example the function of 'be' is provided
by です. は is the topic or contrast marker. For me the distinction between topic
and contrast can be quite blurry, but in these sentences I'd say it's
contrast.

> その店で洋書が売られている  
>  Western books are sold in that shop  
>  その店で **は** 洋書が売られている  
>  I don't know about other shops, but at least in that particular shop,
> western books are sold.

That's obviously an exaggeration, but hopefully you get the idea.

From the topic marker point of view, I'm sure you would be happy with the
following sentence:

> その店はmomokoの店です。  
>  That shop is Momoko's shop.

You've introduced a new topic, 'that shop', to the conversation. But what if
you wanted to talk about what happens **in** the shop? You need to put **で**
on the end, but you're introducing a new topic at the same time so you need a
**は**. No problem, just put the two together and you get your original
example:

> その店 **では** 洋書が売られている

Which of the two interpretations is more appropriate would be determined by
context.




Let me caveat this answer by saying that I've only been learning for a year
and use of は is a mind bending subject.

First of all, は does **not** mean 'be'. If you really think this then you have
a serious misunderstanding. In your example the function of 'be' is provided
by です. は is the topic or contrast marker. For me the distinction between topic
and contrast can be quite blurry, but in these sentences I'd say it's
contrast.

> その店で洋書が売られている  
>  Western books are sold in that shop  
>  その店で **は** 洋書が売られている  
>  I don't know about other shops, but at least in that particular shop,
> western books are sold.

That's obviously an exaggeration, but hopefully you get the idea.

From the topic marker point of view, I'm sure you would be happy with the
following sentence:

> その店はmomokoの店です。  
>  That shop is Momoko's shop.

You've introduced a new topic, 'that shop', to the conversation. But what if
you wanted to talk about what happens **in** the shop? You need to put **で**
on the end, but you're introducing a new topic at the same time so you need a
**は**. No problem, just put the two together and you get your original
example:

> その店 **では** 洋書が売られている

Which of the two interpretations is more appropriate would be determined by
context.

