They started to sing softly.

他们开始轻声唱。

youdao

She closes her eyes again and I begin to sing softly.

她又一次闭上了眼睛，我开始轻声唱。

youdao

Sing softly, beautifully and at a high pitch. Then lay special emphasis on the mixed proportion of the vocal parts so as to display rich and varied musical images.

其次是各声部之间在混合共鸣比例上要有所侧重，以体现合唱声群音色的层次与深度，为表现丰富的音乐形象提供基本可能。

youdao

The light of a full moon shimmered on the plain, and from time to time they saw a rabbit jump, but Pereda paid no attention, and after a long spell of silence he softly began to sing a song in French that his late wife had liked.

NEWYORKER: The Insufferable Gaucho