A, mado-ga aite-iru-yo. (Oh, the window is open.)

Situation 1: Mr. and Mrs. Okubo are drinking tea in their house.

妻： 何だか寒くない？

夫： あ、窓が開いているよ。だから寒いんだ。

Tsuma: Nandaka samuku-nai?

Otto: A, mado-ga aite-iru-yo. Dakara samui-n-da.

Wife: Isn't it cold in here?

Husband: Oh, the window is open. No wonder it's cold.

Today we'll introduce the phrase X(=verb in te-form) いる that shows the state of something. X(=verb in te-form) いる has some usages, and when X is an action verb such as 話(はな)す (to speak) or 読(よ)む (to read), Xている expresses the action in progress, as in 今(いま)、コーヒーを飲(の)んでいます (I'm drinking coffee now). Xている also expresses an experience, as in 私はインドに2回(にかい)行(い)っている (I have been to India twice), and also shows the completion/realization of the action, as in プレゼンはもう始(はじ)まっている (The presentation has already started). When X is an intransitive verb to describe a change of state, such as 開(あ)く (to open) or つく (to turn on), or a verb that shows the continuing state, such as 住(す)む (to live), 知(し)る (to know), Xいる shows the resulting state of a certain change. Examples: 道路(どうろ)がぬれているよ (The road is wet); 弟(おとうと)は今(いま)、タイに住(す)んでいる (My younger brother lives in Thailand now). V(verb in te-form)てる is a colloquial contracted form of V(verb in te-form)いる, and is usually used in casual conversation.

Situation 2: At home. Little Mariko asks her elder sister Takako where their mother is.

まり子： お母さんは買い物に行ったの？

たか子： さっき行ってきて、今は家に帰っているよ。

Mariko: Okāsan-wa kaimono-ni itta-no?

Takako: Sakki itte-kite, ima-wa ie-ni kaette-iru-yo.

Mariko: Has Mom gone shopping?

Takako: She went a few minutes ago, and now she's home.

When X is a verb of movement such as 行く(to go), 来る(to come) or 帰る(to go/come back), Y(name of the place) に X(verb in te-form)いる means that someone/something has already moved to Y and that he/she/it is still in that place. Therefore, 彼(かれ)は東京(とうきょう)に来(き)ている means "He has come to Tokyo and is still here," not "He is coming to Tokyo." Another example: 高橋(たかはし)さんは出張(しゅっちょう)で札幌(さっぽろ)に行(い)っています (Ms. Takahashi is in Sapporo for a business trip).

Bonus Dialogue: Young staff members are chatting before the business seminar.

田町： 三田(みた)さんはもう来(き)てるね。市川(いちかわ)さんは？

三田： まだ来ていないよ。今(いま)、こっちに向(む)かっているってメールが来た。

田町： 市川さん、この前(まえ)の研修(けんしゅう)にも来ていたよね。熱心(ねっしん)ねえ。

グレイ： うん。でも、この前、市川さんが来たとき、研修はもう始(はじ)まっていて、ちょっと恥(は)ずかしそうだった。

三田： 市川さんの仕事(しごと)はお客さんの対応(たいおう)だから、しかたがないよ。

田町： うん。三田さんがメモを取(と)っておいてあげれば？ いいことがあるかも。

三田： えっ、そんなつもりじゃ...。

グレイ： だって、この研修に市川さんを誘(さそ)ったのは 三田さんでしょう？　ちゃんと知(し)ってるよ。 私(わたし)たち、あたたかく見守(みまも)っている。

三田： うん。[ひとりごと]何(なん)だかやりにくいな。

Tamachi: I see Mr. Mita is already here. How about Ms. Ichikawa?

Mita: She isn't here yet. I got an e-mail that she's on her way.

Tamachi: Ms. Ichikawa came to the previous seminar, didn't she? She seems eager.

Gray: Yeah. But when she came to the seminar last time, the class had already started and she looked a little embarrassed.

Mita: Her job is to deal with customers so it can't be helped.

Tamachi: I understand. Mr. Mita, why don't you take notes for her? Some good may come of it.

Mita: What? I don't have any intentions like that.

Gray: You are the person who invited her to this seminar, right? We know all about it. We'll (warmly) watch over you.

Mita: Yeah. (To himself) Gee, this is making me uncomfortable ...