咔嚓

kā chā yī shēng shù zhī duàn le

咔嚓一声，树枝断了。

There was a creaking sound and the branch snapped.

tā tīng dào kā chā yī shēng zhī dào lóng mén yǐ jīng guān shang

他听到咔嚓一声，知道笼门已经关上。

He heard a crack and knew that the cage door had been closed.