Tā búdòng-shēngsè de guānchá zhe zhōuwéi de yíqiè.
She quietly observed everything around her without letting anything show.
Tips
history
From Ouyang Xiu's Song-dynasty 《相州昼锦堂记》: '垂绅正笏,不动声色,而措天下于泰山之安。' - a great minister brings the realm to the stability of Mount Tai without betraying a ripple in voice or expression.
usage
Strong positive or neutral tone - admirable composure, especially under pressure or when planning in secret. Often adverbial with 地: '不动声色地进行'. Contrast with 喜形于色 (joy shows on the face).