英訳例は、直訳ですと、「お土産としては、どのワインがおすすめですか？」という意味です。
こうした which は「どの〜」という意味で、名詞の前に付けて使うことができます。
Which color do you like?
（どちらの色が好きですか？）
Which plan did you choose?
（どちらのプランを選びましたか？）
souvenir は「お土産」で、as a souvenir で「お土産として」の意味になります。
こうした 「〜として」の意味の as の用法としては、次のような文が挙げられます。
She did a great job as a project manager.
（彼女はプロジェクトマネージャーとして、素晴らしい仕事をした）
お役に立てれば幸いです。
What type of wine will you recommend as a souvenir?
What is the best wine to keep as a souvenir?
>What type of wine will you recommend as a souvenir?
Because there are so many different types of wine, it is good to ask what "type".
>What is the best wine to keep as a souvenir?
Because you want to keep it as a souvenir, asking for the "best" wine is good so that you don't keep something that is worthless.
#worthless=having no real value or use
What type of wine will you recommend as a souvenir?
たくさんの種類のワインがあるので、どの「種類」が美味しいか尋ねる時の表現です。
What is the best wine to keep as a souvenir?
価値のないものを購入したくないので、お土産のために「最高」のワインはを尋ねるときの表現です。
#worthless=本当に価値や有用性のないものを意味します。
having no real value or use"
Well, as far as souvenirs go, it can be a very personal thing that reminds you of the place you have visited, so the best souvenir of a place is the thing that you like most that may be taken home. Wine, however is a consumable item so your personal preference may apply. Do you prefer sweet or dry wine? If you prefer sweet wine, you could ask, "Is there a local sweet wine I could buy?"
It could be that you do not intend to drink the wine, so a nice display bottle or bottle on a display rack may be more appropriate if it has some design or name or feature connected with the area. You may just wish to be safe and buy what most people buy and here, of course the local shop assistant will be able to help.
"Which is the most popular wine that tourists buy?"
"It's this delicate white wine with a flavour that has a hint of apple."
"OK, thanks, I'll take two of those."
まー、Souvenirsっていうのはどこまでいっても、自分がその場所へ行ったっていうことを思い出させてくれるすごく個人的なものなんだ。だから自分の家に持ち帰ることのできる一番気に入ったものが一番だと思うよ、ワインっていうのは、消費物だから自分の好みによるよね。甘いワインが好きなら、 "Is there a local sweet wine I could buy?" ときくことができるよ。
その地域の名前やデザインなんかがはいっていれば、飲むようじゃなくてもボトル自体が良いディスプレイになりうるよね。妥当な線で行けば、一番売れているのを買えばいいと思う。もちろん、店の人がきっと助けてくれるよ。
"Which is the most popular wine that tourists buy?" 観光客がかっていく一番人気なワインはどれ？
"It's this delicate white wine with a flavour that has a hint of apple." りんごの隠し味のついたこのワインです。
"OK, thanks, I'll take two of those."ありがとう、これ２つ頂戴。
Which wine would you say is most suitable as a souvenir?
The adjective 'ideal' means 'most suitable' in this context. So, in the first question, it can alternatively be asked: Which wine is most suitable as a souvenir? You may also politely request the other person to simply recommend to you the ideal souvenir wine.
So, you may ask:
Which wine is ideal as a souvenir?
or
Please recommend to me an ideal souvenir wine.
or
Which wine would you say is most suitable as a souvenir?
形容詞'ideal'（理想的な）がこの場合一番合った言葉だと思います。
はじめの質問は、
Which wine is most suitable as a souvenir?
どのワインが一番お土産にいいですか？
と同じような意味になりますが、よりシンプルに丁寧に聞きたいときは以下の表現がいいでしょう。
Which wine is ideal as a souvenir?
どのワインがお土産にいいですか？
Please recommend to me an ideal souvenir wine.
お土産にいいワインのおすすめを教えてください。
Which wine would you say is most suitable as a souvenir?
お土産に一番いいワインのおすすめを教えてもらえますか？
If you are asking someone's opinion on wine, one might assume that it will be gifted to someone or used in the future for a special occasion. It is best to ask someone who knows about wine so that they can give you the best recommendations based on your preferences.
I'd like to take a wine bottle back as a souvenir. Which one would you recommend?
Which of these wine bottles is the best to take back as a souvenir?
Recommend: means asking for someone's opinion or advice on a matter.
If the wine is not to be drunk, and only to be displayed somewhere, you can specify that to the seller by saying "I don't want to drink the wine but would like to put it up on a mantelpiece."
mantelpiece: is a place above a dresser that has ornaments on it.
Or if you're buying it for a friend you can say "It is a gift for my friend back home."
Hope this helps!
Recommend: ある事柄について人の意見又はアドバイスを求めること。
ワインを飲むのではなくどこかに飾りたいのであれば、そのことを明確に伝えます：
"I don't want to drink the wine but would like to put it up on a mantelpiece."
（ワインは飲むのではなく、mantelpieceに飾りたいのです）
mantelpiece: 飾りが置かれる鏡台の上の場所
もし友人にワインを買いたいのであれば、こんな風に言えます：
"It is a gift for my friend back home."
（それは地元の友人へのプレゼントです）
When buying wine as a gift, it is important to ask someone, especially if that person collects it. You want something that can maybe age well or maybe you want something that is not common in your region.
"Which wine would you recommend as a souvenir?"
ワインをお土産として買うとき、その人がワインのコレクターだったらとくに、どのワインが欲しいか聞くことは重要です。年代物のワインが欲しいかもしれないし、その地域でよく飲まれるワインがほしいかもしれません。
"Which wine would you recommend as a souvenir?"
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