Ja, ima, isogashii-wake-da. (Well then, she must be busy right now.)

Situation 1: Ms. Tamachi and Ms. Gray are planning a trip to a hot spring and are talking about whom to invite.

田町： 山下さんは先月、双子の赤ちゃんが生まれたんだって。

グレイ： ああ、じゃ、今、忙しいわけだ。しばらく旅行は無理ね。

Tamachi: Yamashita-san-wa sengetsu, futago-no akachan-ga umareta-n-da-tte.

Gray: Aa, ja, ima, isogashii-wake-da. Shibaraku ryokō-wa muri-ne.

Tamachi: Ms. Yamashita had twins last month, I heard.

Gray: Well then, she must be busy right now. I bet it'll be impossible for her to go on a trip for a while.

Today we will introduce the sentence-ending expression Xわけだ, which is used when the speaker wants to explain a reasonable and logical conclusion — X — derived objectively from what the speaker has found or heard. X is a verb, i-adjective, na-adjective or noun sentence in noun-modifying form. In Ms. Gray's remark, Xわけだ expresses the inevitable conclusion from what Ms. Gray said. Words such as じゃ (then) and ということは (that means) are usually used in sentences with Xわけだ. Examples: 「毎月(まいつき)２万円(にまんえん)貯金(ちょきん)するんだ。」 「ということは、年(ねん)に 24万円(にじゅうよんまんえん)貯(た)まるわけだね。」 ("I will save ¥20,000 per month." "That means you will save up ¥240,000 a year"). Xわけだ is also used when the speaker puts what he/she heard or said in other words. In this case, words such as つまり(in short) or じゃ(then) are often used at the beginning of the sentence. Example: 町中(まちじゅう)、クリスマスセールですね。」 「つまり、 今年も終(お)わりというわけですね。」 ("There are Christmas sales on all over town." "In short, then, the year is just about over.")

Situation 2: Mr. and Mrs. Okubo are watching a TV show and chatting about an actor who sings very well.

妻： この人は昔、ミュージカルに出ていたときもあるのよ。

夫： ああ、だから、歌が上手なわけだ。

Tsuma: Kono hito-wa mukashi, myūjikaru-ni dete-ita toki-mo aru-no-yo.

Otto: Aa, dakara, uta-ga jōzuna-wake-da.

Wife: He once used to perform in musicals, you know.

Husband: Oh, then, it's only natural that he would be good at singing.

Xわけだ also shows the speaker's conviction, and in this context, words such as だから (so), それで (then) and どうりで(no wonder) are often used together. This pattern is often used when the speaker hears the counterpart's remark or notices a certain fact and is now convinced of X, with their doubt having evaporated. Example:トムは日本(にほん)の大学(だいがく)を卒業(そつぎょう) したんですか。どうりで日本(にほん)についてよく知(し)っている わけですね (Tom graduated from a Japanese university, right? So, that explains why he knows so much about Japan).

Bonus Dialogue: Ms. Tamachi and Mr. Sere are talking about cakes Ms. Tamachi had left on her desk. Later, Ms. Gray cuts in.

田町： あっ、私(わたし)のお菓子(かし)がない。これから食(た)べようと思(おも)っていたのに。犯人(はんにん)は三田(みた)さんね。さっきおなかがすいて、何(なに)か食(た)べるものがないかって聞(き)いてたのよ。

セレ： じゃ、三田くんが食べたわけ？でも、いくら三田くんでも、そんなことをするかな。

田町： だって、お菓子がなくなっているもの。三田さん以外(いがい)考(かんが)えられない。

セレ： つまり、田町さんは三田さんがそういう人(ひと)だと思(おも)っているわけだ。

グレイ： [会話(かいわ)に入(はい)る] え？あのお菓子、田町さんのだったの？ごめんなさい。私の机(つくえ)のはしにあったから、私のだと思って食べちゃったのよ。

田町： ええっ？お菓子はグレイさんの机(つくえ)のほうに行(い)っちゃったんだ。それで、グレイさんが食べちゃったわけね。三田さんを疑(うたが)って悪(わる)かったわ。

セレ： かわいそうな三田くん。犯人にされて。

グレイ： でも、これで事件(じけん)は解決(かいけつ)したわけね。

Tamachi: Oh, my cakes are missing. I was going to eat them now. The culprit must be Mr. Mita. He said he was hungry earlier and asked me if there was anything to eat.

Sere: So, you're saying that Mr. Mita ate them, right? But I wonder if even he would do such a thing.

Tamachi: But my cakes have gone. It couldn't be anyone but him.

Sere: In short, then, you think he's that kind of a person.

Gray: [Cutting in on the conversation] What? Were those cakes yours? Sorry. They were on the edge of my desk and I thought they were for me. So I ate them.

Tamachi: What? So my cakes got moved onto your desk? And you ate them? I feel awful about ever suspecting him.

Sere: Poor Mita! He was suspected of being the criminal.

Gray: Anyway, at least this case has been solved.