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I would like to know what's the difference of じゃん and だろう／でしょう.

the meaning I know it's similar, but when I should use each of them?

Is it same to say:

> これはすごいじゃん！ ＝ これはすごいでしょう！ ＝ これはすごいだろう！
>
> 昨日、楽しかったじゃん？ ＝ 昨日、楽しかったでしょう？ ＝ 昨日、楽しかっただろう？
>
> できるじゃん！ ＝ できるでしょう！

thanks
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2011-08-06T07:10:34.260
2489
2011-12-27T16:56:21.557
2020-06-17T08:18:27.500
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question
usage dialects
the difference between じゃん (jan) and だろう/でしょう (darou/desho)
じゃん is じゃないか, i.e., ではありませんか

When you say "すごいじゃん", you actually _affirm_ "that's great, isn't it?", you
give your opinion, and don't care about any one else. The intonation is that
of a strong affirmation.

だろう/でしょう is rather an introspective form, or an "open to suggestions"
affirmation. When you say "すごいでしょう", you say "that's great, isn't it" and you
look at the people around you, expecting an agreement, a reaction. The
intonation is that of a question.

できるじゃん! is something you say while doing it: "see, I can do it!". Though more
naturally, I'd say "できたじゃん" or "できているじゃん".  
できるでしょう is something you say before he does it: "I'm pretty sure he can do it,
can't he?"  
(If I were to say "I'm pretty sure I can do it", I'd say it differently,
that's why the subject changes in my example.)

Also, grammar dictates that you can't say すごいだろう, so usage has it like
"すごいんだろう", when you want to leave politeness apart (even though でしょう as in the
example above is perfectly ok in informal conversations).
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2011-08-06T07:58:46.667
2490
2011-08-06T07:58:46.667
356
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answer