Her expression was glacial.

她表情冷淡。

《牛津词典》

Her expression grew solemn.

她的表情显得严肃起来。

《牛津词典》

Her expression suddenly altered.

她的表情突然变了。

《柯林斯英汉双解大词典》

As she accepted the Intellectual Property Owner's Association 's 27th Annual Inventor of the Year award on June 28 for her work in tissue engineering--she is the first individual woman to win the award--her Donna Reed-style hair and her concerned expression made her look like a doctor about to apply a Band-Aid.

FORBES: Advanced Tissue Sciences Founder Wins Inventor Award

Streep's Jane giggles a lot -- either the expression of her joie de vivre, or else a tic.

CNN: Review: 'Complicated' lavishes attention on stuff

As he begins to backtrack, she jolts upright, stares back in shock, then in mock shock, shifting in subtle increments until she smiles, lets her face go blank again, and leans back into his arms with relaxed panic, a twenty-sided facial expression that should earn Lauren Graham a special Emmy.

NEWYORKER: Warming Trend