She has a vacant look on her face.

她的脸上是一片茫然的神色.

She has that glazed , vacant look about her.

她说，玻璃，看看她的空缺。

The nodding and vacant look on their faces is a straw in the wind .

他们昏昏欲睡和空洞的表情是打瞌睡的征兆。

From her vacant look we can know that she probably is in bad condition.

从她发呆的样子我们可以知道她也许身体不好.