2 sentences

1. 维修工终于查出了故障的原因。

   wéi​xiū​gōng zhōng​yú chá​chū le gù​zhàng de yuán​yīn.

   The repairman finally found the cause of the fault.

   Source: Dong Chinese Dictionary

2. 经过仔细检查，维修工终于查出了故障的原因。

   jīng​guò zǐ​xì jiǎn​chá, wéi​xiū​gōng zhōng​yú chá​chū le gù​zhàng de yuán​yīn.

   After a careful inspection, the repairman finally found the cause of the malfunction.

   Source: Dong Chinese Dictionary