1 sentence

1. 金属疲劳是导致这起机械事故的主要原因。

   jīn​shǔ pí​láo shì dǎo​zhì zhè qǐ jī​xiè shì​gù de zhǔ​yào yuán​yīn.

   Metal fatigue was the main cause of this mechanical accident.

   Source: Dong Chinese Dictionary