1 sentence for 坏事 (huài​shì — ruin things)

1. 我本想帮忙，没想到反而坏事了。

   wǒ běn xiǎng bāng​máng, méi xiǎng​dào fǎn'ér huài​shì le.

   I intended to help, but I didn't expect to mess things up instead.

   Source: Dong Chinese Dictionary