婴儿的听觉很敏感,突然的噪音容易把他吓醒。Yīng'ér de tīngjué hěn mǐngǎn, tūrán de zàoyīn róngyì bǎ tā xià xǐng.A baby's sense of hearing is very sensitive, and sudden noise can easily wake him up with a fright.
婴儿一天要睡很长时间。Yīng'ér yì tiān yào shuì hěn cháng shíjiān.A baby has to sleep for a long time every day.
妈妈轻轻地抱着婴儿,哼着歌哄他睡觉。Māma qīngqīng de bàozhe yīng'ér, hēngzhe gē hǒng tā shuìjiào.Mum held the baby gently and hummed a song to lull him to sleep.