on pins and needles 如坐针毡；坐立不安

【例句】
The father-to-be is on pins and needles.
即将成为父亲的人紧张地如坐针毡。

Many famous actors are on pins and needles before the curtain opens for a play.
在帷幕拉开前，许多著名的演员感到坐立不安。