ものなら②

If you were to do, If you try to, If … happens, Should there be

彼女かのじょの誕生日たんじょうびを忘わすれようものなら、一日中いちにちじゅう機嫌きげんが悪わるくなる。

If you were to forget her birthday, she would be in a bad mood all day.

Explanation

「Vようものなら」 means 'if you dare to ...'. It supposes a risky, rude or mistaken action, and what follows is always a serious consequence, never something good: 「少しでも反論しようものなら、上司に怒鳴り散らされる」 (If you so much as argue back, the boss will shout at you), 「約束の時間に1分でも遅れようものなら、彼女の機嫌は一日中直らない」 (If I'm even one minute late, she'll be in a bad mood all day). It sounds like a warning not to try it.

Mixed up with

Potential verb＋ものなら: 'if only I could ...', a wish that is hard to fulfil, e.g. 「戻れるものなら、過去に戻りたい」 (If I could, I'd go back to the past).

Volitional verb＋ものなら: this entry, 'if you dare ... you're in trouble'; disaster or scolding follows.

The verb form (potential vs volitional) and the meaning are completely different, a classic N1 trap.

Examples

このレポートを出だし忘わすれようものなら、今いままでの努力どりょくが水みずの泡あわだ。
All of our efforts would be worth nothing, if I happen to forget to submit this paper.
ブラッド・ピットに出逢であおうものなら、死しんでしまう。
If I were to run into Brad Pitt, I would die.
しのぶさんはとても血ちを恐おそれている。万まんが一いち、一滴いってきでも血ちを見みようものなら気絶きぜつしてしまうはずだ。
Shinobu is completely terrified of blood. If she were to see even one drop of it by chance, she would faint for sure.
以前いぜん同おなじようなことで炎上えんじょうしたから、また似にたようなことで炎上えんじょうしようものならこの業界ぎょうかいから干ほされるに違ちがいない。
Since we went under fire with something similar before, if we go under fire for something similar again, I am sure we would be sidelined from this industry.
秘密ひみつを打うち明あけようものなら、彼女かのじょはすぐに他ほかの奴やつらにしゃべってしまうだろう。
If you happen to tell her a secret, she will quickly spill it to others.
万まんが一いちこのプロジェクトが失敗しっぱいしようものなら、我々われわれは終おわりだ。
If this project were to fail, we'd be finished.
うっかり彼かれのお菓子かしを食たべようものなら、きっと、ものすごく彼かれにしかられるはずだ。
If you were to go and eat his sweets, you would be scolded for sure.
これは大変たいへんデリケートな機械きかいだからもし少すこしでも力ちからを入いれようものなら壊こわれるかもしれない。
It's a very delicate device, so if we were to put even the slightest pressure on it, it may break.