7.3 Uncertainty

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Overview

Learn to express guesses and wonder using でしょう and だろう for probability, でしょうか and だろうか for polite or casual wondering, and かな for thinking out loud.

でしょう — guess / probability

でしょう is used to express a polite guess or likely assumption. It often corresponds to “probably” or “I think …”.

。

It will probably rain tomorrow.

。

He has probably already arrived.

だろう is the casual counterpart of でしょう.

。

It will probably rain tomorrow.

。

It’s probably finished already.

でしょうか — uncertainty / soft question

でしょうか is used when politely asking for confirmation or opinion.

。

Is this correct, I wonder?

。

Will tomorrow be okay?

It can also be used to express “I wonder…”

。

I wonder if he will come.

だろうか is the casual version of でしょうか. It often sounds like the speaker is thinking out loud.

。

I wonder if he will come.

。

I wonder if I’ll make it on time.

だろうか is almost identical to かな, but it has a bit more skeptical feeling to it.

かな — wondering to oneself

かな is a very casual way to express personal doubt or wondering. It often feels like talking to yourself.

。

I wonder if it will rain today.

。

I wonder if this is okay.

かな does not directly ask the listener for an answer. It simply expresses uncertainty.

Tone comparison

Expression	Politeness	Usage
でしょう	polite	soft guess
だろう	casual	casual guess
でしょうか	polite	polite wondering
だろうか	casual	casual wondering
かな	casual	casual wondering

Points to keep in mind

でしょう / だろう express probability
でしょうか / だろうか soften questions and express personal wondering
かな expresses personal wondering

Dialogue

きょう今日はあさ朝からそら空がくもっています曇っています。ごご午後はあめがふる雨が降るでしょう。かさ傘をもっていった持っていったほうがいいかな。ともだち友達とのやくそく約束はさんじ三時でしたが、まだれんらく連絡がありません。もうしゅっぱつ出発しているだろうか。でんしゃ電車がおくれている遅れているのでしょうか。かふぇカフェのまえ前でまち待ちながら、いろいろかんがえていました考えていました。かのじょ彼女はこうひいコーヒーがすき好きだから、このかふぇカフェをきにいる気に入るでしょう。まど窓のそと外をみる見ると、ひと人がすくなくなって少なくなってきました。みんなあめがふる雨が降るまえ前にかえった帰ったのだろう。そのうちともだち友達からきごう「いま今ついた着いたよきごう」とめっせえじメッセージがきました来ました。やっぱりでんしゃ電車がおくれた遅れたのでしょう。きょう今日はけっきょく結局あめ雨にはならなかったけど、せいかい正解だったかな。

The sky has been cloudy since this morning. It will probably rain in the afternoon. I wonder if I should take an umbrella. I had an arrangement to meet a friend at three, but I still haven't heard from them. I wonder if they've already set off. I wonder if the train is running late. While waiting in front of the café, I was thinking about all sorts of things. Since she likes coffee, she will probably like this café. Looking out the window, the number of people had started to thin out. They probably all went home before the rain. Before long, a message came from my friend saying, "I just arrived." The train must have been delayed after all. In the end it didn't rain today — but I wonder if I was right to worry.

Grammar

Title	Description
～でしょう	polite guess or probability ("probably")
～だろう	casual guess or probability ("probably")
～でしょうか	polite wondering or soft question ("I wonder if")

7.2 Explanation

7.4 Limitation

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