"This is all that's in stock." - The phrase 'this is all' means that there is nothing more in stock or there are no other colours or sizes available.
"What is there is all that we have" - In this sentence, 'there' could refer to the shelf whereby you find a product. Therefore, the items on the shelf is all that is available, there is nothing more or there are no alternatives.
例：This is all that's in stock.
「それが在庫の全てです。」
'this is all'で「これで全て」という意味で、（色、サイズ等含め）他にはないということです。
例：What is there is all that we have.
「そこにあるものが全てです。」
'there'は棚を指し、「棚に有るものが全てです。」と言えます。
"We only have what's out" is the most simple and straightforward way to say this.
"Everything we have is on display" is a more formal way to say this.
"We only have what's out"（出ているものがすべてです。）
という表現は一番シンプルで相手に伝わりやすいでしょう。
"Everything we have is on display"（ディスプレイされているものがこの店にある全ての商品です。）という文章はよりフォーマルな言い方です。
Explanation: The above sentences are pretty typical for the UK. However people often ask about other colours, sizes etc because shops often keep backup stock in their store rooms.
Example sentence:
A. "Do you do this in blue?"
B. Sorry, if you can't see it, we don't have it.'
解説：上記のフレーズはとても典型的なイギリスの表現です。しかし、お客さんは店の倉庫にしまってあるかもしれない他の色やサイズについて尋ねることもあるでしょう。
例文：
A. "Do you do this in blue?"（この青色はありますか？）
B. Sorry, if you can't see it, we don't have it.'（すみません。そこにある分しかありません。）
When talking about what we have for sale, we can use the term, "on display," to talk about the items that we put out for customers to see as an offer. We can also talk about what things are only, "offered," as well.
"Sorry but I only stock what is in the fridge." This politely apologizes for not having what they want and explains that you only have what is in the fridge.
"Sorry I only have what you see in the fridge." This also politely apologizes and explains that you only have the products or brand that are in the fridge at that time.
"Sorry but I only stock what is in the fridge."
（すみません、在庫は冷蔵庫にあるだけです）
これは丁寧に欲しいものがない事を謝り、在庫は冷蔵庫にあるだけだ、と説明しています。
"Sorry I only have what you see in the fridge."
（すみません、ご覧のとおり冷蔵庫の中だけです）
これもまた丁寧に謝り、商品は冷蔵庫にそのときあるだけです、と言う事を説明しています。
*In stock are only those things on display.- Stock means what is available in warehouse or storage room.
A: Do you have this dress in size 12?
B: I'm sorry only those dresses on display are left, we are running out of stock.
*In stock are only those things on display.-
在庫はディスプレイのものしかありません。
Stockとは倉庫や保管庫の中にある在庫のことです。
A: Do you have this dress in size 12?
このドレスの１２号はありますか？
B: I'm sorry only those dresses on display are left, we are running out of stock.
申し訳ございません。在庫を切らしておりディスプレイのものしかありません。
We are only selling display stock...so what you see ...is what you get;-)
What you see is what you get...is a clear message in terms of outcome...We cannot possibly hold very color or brand in the world:-D
"We are only selling display stock...so what you see ...is what you get;-)"
What you see is what you get.
（そこにあるものだけしかありません。）
これは結果についての明瞭なメッセージです。私達は世界中のすべての色やブランドを手にすることはできません。
例文；
"We are only selling display stock...so what you see ...is what you get."
(販売中の在庫は展示してあるもののみです。ですので、そこにあるだけのものしかありません。）
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