Zitat
Coming to a conclusion with 「わけ」
The first type of grammar is, in actuality, just a regular noun. However, it is used to express a concept that deserves some explanation. The noun 「わけ」(訳) is defined as: "meaning; reason; can be deduced". You can see how this word is used in the following mini-dialogue.
Mini-Dialogue 1
(直子) いくら英語を勉強しても、うまくならないの。
- No matter how much I study, I don't become better at English.
(ジム) つまり、語学には、能力がないという訳か。
- So basically, it means that you don't have ability at language.
(直子) 失礼ね。
- How rude.
As you can see, Jim is concluding from what Naoko said that she must not have any skills at learning languages. This is completely different from the explanatory 「の」, which is used to explain something that may or may not be obvious. 「わけ」 is instead used to draw conclusions that anyone might be able to arrive at given certain information.
A very useful application of this grammar is to combine it with 「ない」 to indicate that there is no reasonable conclusion. This allows some very useful expression like, "How in the world am I supposed to know that?"
(1) 中国語が読めるわけがない。
- There's no way I can read Chinese. (lit: There is no reasoning for [me] to be able to read Chinese.)
Under the normal rules of grammar, we must have a particle for the noun 「わけ」 in order to use it with the verb but since this type of expression is used so often, the particle is often dropped to create just 「~わけない」.
Mini-Dialogue 2
(直子) 広子の家に行ったことある?
- Have you ever gone to Hiroko's house?
(一郎) あるわけないでしょう。
- There's no way I would have ever gone to her house, right?
Mini-Dialogue 3
(直子) 微積分は分かる?
- Do you understand (differential and integral) calculus?
(一郎) 分かるわけないよ!
- There's no way I would understand!
There is one thing to be careful of because 「わけない」 can also mean that something is very easy (lit: requires no explanation). You can easily tell when this meaning is intended however, because it is used in the same manner as an adjective.
(1) ここの試験に合格するのはわけない。- It's easy to pass the tests here.
Finally, although not as common, 「わけ」 can also be used as a formal expression for saying that something must or must not be done at all costs. This is simply a stronger and more formal version of 「~てはいけない」. This grammar is created by simply attaching 「わけにはいかない」. The 「は」 is the topic particle and is pronounced 「わ」. The reason 「いけない」 changes to 「いかない」 is probably related to intransitive and transitive verbs but I don't want to get too caught up in the logistics of it. Just take note that it's 「いかない」 in this case and not 「いけない」.
(1) 今度は負けるわけにはいかない。
- This time, I must not lose at all costs.
(2) ここまできて、あきらめるわけにはいかない。
- After coming this far, I must not give up.
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