Mō chūgakusei-nan-dakara (You're already a junior high school student.)

Situation 1: At the Okubo family's house.

たか子： お母さん、制服のボタンが取れちゃったから、つけてくれる？

母： たか子は、もう中学生なんだから、ボタンぐらい自分でつけなさい。

Takako: Okāsan, seeifuku-no botan-ga torechatta-kara, tsukete-kureru?

Haha: Takako-wa, mō chūgakusei-na-n-dakara, botan-gurai jibun-de tsukenasai.

Takako: Mom, a button has come off my school uniform. Will you fix it for me?

Mother: Takako, you're already a junior high school student. So, you should sew it on by yourself.

Today, we will introduce various ways of using the adverb もう (already/no more). The pattern もうX(phrase) means that something is already in a certain condition (X) and expresses the speaker's feelings about that condition, such as surprise, or in the way the mother uses it in Situation 1 as way to complain or give a warning. When the negative form of X is used, もう expresses that the condition is not X anymore. So, the mother's phrase can be changed to: "もう小学生（しょうがくせい）じゃないのだから (Since you're not a pupil of elementary school any more)."

Situation 2: At her office, Ms. Gray takes a telephone call for Ms. Tamachi.

グレイ： 田町は今、席をはずしております。もう戻ると思いますが、折り返しお電話いたしましょうか。

客： いえ、大丈夫です。もう一度こちらからかけますので。

Gray: Tamachi-wa ima, seki-wo hazushite-orimasu. Mō modoru-to omoimasu-ga, orikaeshi odenwa-itashimashō-ka.

Kyaku: Ie, daijōbu-desu. Mō ichido kochira-kara kakemasu-node.

Gray: Ms. Tamachi is not at her desk right now. I think she'll be back soon. Shall I ask her to call you?

Customer: No, thank you. I'll call her again.

もう also means that a certain condition will be met soon, as in Ms. Gray's second sentence in Situation 2, or as in "もう終（お）わるから、ちょっと待（ま）っていて (I'll finish soon; will you wait for a while?)." The customer's use of もう of もう一度（いちど） in Situation 2 is in the another usage that means to add one more thing, some more of a quantity or degree. Examples: "私（わたし）の、もう片方（かたほう）のてぶくろ、見（み）なかった？ (Have you not seen my other glove?)." "もう少（すこ）し大（おお）きい声で言 （い）ってください (Please speak a little louder)."

When the speaker wants to emphasize the feeling that he/she does not want to repeat or continue something any more, もう is used as in: "戦争（せんそう）は、もういやだ (I'm tired of war)."

Bonus Dialogue: While Mr. Sere is walking down a corridor he finds Mr. Mita coming out of a room with a suitcase. Later, their boss Mr. Okubo also passes by.

セレ： あ、三田（みた）くん、もう帰（かえ）るの？早（はや）いね。

三田： うん。今日（きょう）の仕事（しごと）は、さっさとすませたんだ。今夜（こんや）は大事（だいじ）な用（よう）があるから。

セレ： あれっ、今夜は大宮（おおみや）くん主催（しゅさい）の合（ごう）コンじゃなかったっけ？

三田： なんだ、セレくん、知（し）ってたの？大事な用って、それのことだよ。彼女のいない生活（せいかつ）とは、もうさよならしたいから。

セレ： 幸運（こういうん）を祈（いの）るよ。

大久保： ［とおりかかる］あ、三田くん、まだいたのか、よかった。プロジェクトの資料（しりょう）がきゅうに必要（ひつよう）になったから、会議室（かいぎしつ）まで、すぐ持（も）ってきて。たのんだよ。［とおりすぎる］。

セレ： 三田くん、合コンには、遅刻（ちこく）だね。

三田： うん。もう少（すこ）しで帰れるところだったのに、残念（ざんねん）。ぼくはいつも、こんなふうにタイミングが悪（わる）いんだ。やっぱり、もうしばらく、彼女のいない生活が続（つづ）くのかも...。

Sere: Oh, Mita, are you leaving so early?

Mita: Yeah. I finished my tasks as early as possible, since I have an important event this evening.

Sere: But, this evening, won't you be joining the group date that Mr. Omiya organized?

Mita: Oh, you already know. Yes, that's the very important event I mentioned. I want to say goodbye to my single life.

Sere: Good luck!

Okubo: (Passing by) Hey, Mr. Mita, I'm glad you're still here. I urgently need that document for the project. Please bring it to the conference room at once, OK? (He leaves).

Sere: Mr. Mita, you'll be late for the party.

Mita: Yeah, I'm sorry that I wasn't able to leave a little earlier. I always have bad timing like this. Well, it looks like I'll be living the single life for a while longer.