妈妈轻声说“嘘嘘”，让吵闹的孩子们安静下来。

Mom softly said '___shh-shh' to quiet the noisy children.

妈妈轻轻发出嘘嘘声，哄宝宝入睡。

The mother made soft ___shh-shh sounds to lull the baby to sleep.