ǒu rán
偶然事故
ǒu rán shì gù
Accidental incident
偶然因素
ǒu rán yīn sù
Random factor
出现这一情况十分偶然。
chūxiàn zhè yī qíngkuàng shífēn ǒurán.
The occurrence of this situation is quite accidental.