L191 may not, must not
キーセンテンス:You may not bring food or drink into the library.

By the way Rosa, would you mind if I joined you for lunch?

Yes, I would mind. You must not sit next to me.
Just kidding!
DIALOGUE – 会話全文
Carrie: Sir, you may not bring food or drink into the library.
Harrison: Oh, sorry. Is there a place where I can eat my lunch?
Carrie: There is a bench outside. You can eat there.
Harrison: Thank you. I’ll do that.
Carrie: Would you mind if I joined you? It’s my lunch break too.
Harrison: Sure. So, even library staff can’t eat inside the building?
Carrie: Actually, we can. I just want to eat outside today.
Harrison: Well, be my guest.
Would you mind あなたは気にしますか?嫌な気がしますか?
※返事「いいですよ」= No だが Sure. も使える
library staff 不可算名詞のstaff
be my guest ご遠慮なくどうぞ = Please do. どうぞやってください

For all of you out there, who are thinking of
checking out our textbook, be my guest.

CHECK YOUR GRAMMAR!
関係副詞 where
Is there a place where I can eat my lunch?
昼食を食べてもいい場所はありますか。
a place where SV 「S が V する場所」
where:後続の節に「〜の場所で私が昼食を食べられる」※場所を示す空所があることを予告
Ex)
I know a place where we can talk in private.
2人きりで話すことができる場所を知っているよ。
相手の意向を尋ねる丁寧な文
Would you mind if I joined you?
私がご一緒してもいいですか。
mind:気にする、迷惑に思う「~したら迷惑に思いますか?」→「~しても構いませんか?」
if I joined you. 仮定法のjoined ※joinでもよいが丁寧度は下がる
BUILD UP YOUR VOCABULARY
may not 公的・権威による禁止
You may not bring food or drink into the library.
飲食物は図書館に持ち込んではなりません。
mayのイメージ「開かれたドア」
→ 目上の者が目下の者にドアを開いて許可をする/してあげる = mayの「許可」には敬意が感じられている

Because of this nuance of “may”,
here “may not” suits this situation, right?

Yes.
Because obviously, the librarian is in a position of authority,
you know, so yeah, “may not” is a perfect fit.
must not 個人的で高圧的な禁止
Hey, you mustn’t bring food or drink into the library.
ちょっと、飲食物は図書館に持ち込んじゃダメだよ。
must:主観的な「~しなければならない」→「ダメだよ」のニュアンス
have to と must not の比較
You have to have your hair cut
You must have your hair cut.
(理髪店に行って)髪を切らなければなりませんよ。
客観的な have to:(明日面接だから)髪を切る必要があるよ
主観的な must:単に話し手の「切らないといけないよ」と言う考え

Could you give me one situation respectively?
respectively:それぞれの、各々の

Sure.
Well, for example, for “have to“, it could be a situation
where you’re going for a job interview.
And for the job interview, you have to have your hair cut.
There’s a certain length of hair that’s required for that job.

Whereas with “must“, I would imagine a situation like a mother
talking to her adolescent son and she hates the way his hair looks.
So she says to him, “Hey, come on! You must have your hair cut”.
EXPRESS YOURSELF IN ENGLISH!
1). 夕食時にスマートフォンを使ってはなりません。
2). もしそうしたくなかったら、あなたは私と一緒に来る必要はありません。
↓
↓

本当はAnswerをmoreタグで折りたたみたい…
↓
↓
ANSWER
1). You may not use your phone at the dinner table.
at the dinner table 夕食時に
at+場所 = そこでの活動を頭に思い浮かべる Ex) at the office = working

So, “at the dinner table” means when you’re having dinner, right?

That’s right. You’re not just sitting at the table.
You’re having dinner at the table.

And it’s interesting because “at almost always implies action”.
For example, “He’s at the office”. That means he’s working, alright?
Whereas, “He is in the office” just describes the places
where he happens to be.
2). You don’t have to come with me if you don’t want to.

Hey, guys.
How about we go out for dinner together this evening
after the recording?

You know, I’m a very important person
and I have tons of things to do…

You know, you’re right.
You don’t have to come with us if you don’t want to.

In fact, it’s probably better that way.
おまけ:独学で英語を勉強しているまねこが使っている英語学習本
オドロキモモノキ英語発音
まねこはこれで 日本語イングリッシュを矯正しました!
英単語の語源図鑑 / 続 英単語の語源図鑑
単語の語源をすると、「イメージで覚える」事ができるます!
新しい単語も「こんな意味かな?」と考える事ができるようになりました。

オススメの英語学習BOOK達です!