〜ものなら

With the potential form, 〜ものなら sets up a condition the speaker thinks is unlikely or impossible, expressing a wish or a challenge; the same verb is often repeated (行けるものなら行きたい／やれるものならやってみろ). With the volitional form (〜ようものなら) it warns that if such a thing were to happen, a serious bad result would follow. Both are emotional and mainly spoken or literary; don't confuse the potential pattern with the plain conditional なら, which has no sense of improbability.

• 行けるものなら、今すぐ故郷へ帰りたい。

  いけるものなら、いますぐこきょうへかえりたい。

  If I could, I'd go back to my hometown right now.

• やれるものなら、自分でやってみろよ。

  やれるものなら、じぶんでやってみろよ。

  If you think you can do it, go ahead and try it yourself.

• 父の前でそんなことを言おうものなら、大変なことになる。

  ちちのまえでそんなことをいおうものなら、たいへんなことになる。

  If you dared say such a thing in front of my father, there'd be trouble.