及其

有关部门正在对这起特大交通事故的发生原因及其造成的直接损失展开联合调查。

yǒu guān bù mén zhèng zài duì zhè qǐ tè dà jiāo tōng shì gù de fā shēng yuán yīn jí qí zào chéng de zhí jiē sǔn shī zhǎn kāi lián hé diào chá.

Relevant departments are conducting a joint investigation into the cause of this major traffic accident and the direct losses caused.