heart stand still
be very frightened or worried提心吊胆；惊恐至极；十分担心
Her heart stood still when she saw her son run into the street in front of a car．看到她儿子跑到街上一辆小汽车前面时她吓坏了。
Everybody's heart stood still when the President announced that war was declared．总统宣战时每一个人都忧心忡忡。