听到熟悉的旋律,她不由自主地跟着轻声哼唱。Tīngdào shúxī de xuánlǜ, tā bùyóuzìzhǔ de gēn zhe qīngshēng hēngchàng.Hearing the familiar melody, she involuntarily hummed along softly.
他紧张得不由自主地发抖。Tā jǐnzhāng de bùyóuzìzhǔ de fādǒu.He was so nervous that he trembled involuntarily.
音乐一响起,大家就不由自主地跳起舞来。Yīnyuè yì xiǎngqǐ, dàjiā jiù bùyóuzìzhǔ de tiào qǐ wǔ lái.As soon as the music started, everyone began to dance without meaning to.