TAKOBOTO

cannot; have no other choice but
Because my boss said so, I have no other choice but to go on this business trip.
しなければならないことについて

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いちにんでやるのはたいへんですが、みんないそがしそうなのでてつだってもらうわけにはいきません。

It is difficult to do alone but since all seem to be busy, I cannot ask them for help.

ふつうのアメリカのパーティーでにほんごをはなすわけにはいきません。

We can't very well speak Japanese at a normal American Party. (The speaker has the ability to speak Japanese, but cannot do it even if he/she wants to because it his inappropriate to speak Japanese in this particular situation.

これはせんせいのほんだから、あなたにかすわけにはいきません。

Since this is my teacher's book, I can't very well lend it to you

かいをけっせきするわけにはいきません。（りゆうがあって、できない）

You cannot be absent for the meeting (for unstated reasons).

あなたにおごってもらうわけにはいきません。（しなければならない）

I cannot allow myself to be treated to this meal by you. (I have to pay).

おおくのひとがたいふうにいえをとられたので、うでぐみでみるわけにはいかない。

Because of storm, many people lost their houses, so I can't ignore

かれのしででをかんたんにことわるわけにはいかない。

I can`t very well decline her offer.

きみのことをしんぱいしないわけにはいかない。

I can`t help feeling anxious about you.

われわれは、かれのしたむせきにんなこうどうをみのがすわけにはいかないのである。

It is because we cannot overlook his behavior of irresponsibility anymore.

もう９じをすぎているが、このしごとをおえるまではかえるわけにはいかない。

It is more than 9PM, but until I can finish that work, I cannot get back home.

あしたはほかのしごとをしなければならないのだから、このしごとをやりかけのまま、かえるわけにはいかない。

As I have to do another work tomorrow, and this one is unfinished as it is, I cannot get back home.

＊Be very careful as to when you replace one of these phrases with another.

Ｖ + しかない : used in a situation where one has no choice but to do something.

Ｖneg + ざるを得ない : used in a situation where one has no choice but to do something.

Ｖneg + なければならない : used in a situation where one has to do something because s/he has an obligation to do it OR where one has no choice but to do something.

Ｖneg + わけに(は)いかない : used in a situation where one has to do something because s/he has an obligation to do it OR where one has no choice but to do something. It also expresses the unwillingness of the speaker to do Ｖ.

rubyhatchet

I think 手伝ってもらうわけにもいきません means "I cannot ask them for help" rather than "I cant get help". No big difference in English?

Miki

I changed ex #5816 according to the alert of Mikiさん.

赤毛

i don't understand... if I have to use "Vneg+ wakenihaikanai" why in the examples you use the Verb in POSITIVE form? the meaning change? the rule can change?

yukito90

It looks like this grammar is used for moral obligations and not physical impossibilities. Therefore, I would translate it as "Mustn´t"

DrJones

Just take the double negative as "I must do" and the others as "I connot do"

masakitenchi