as poor as a church mouse字面意思是“穷得像教堂里的老鼠”，引申为赤贫的；一贫如洗。

【例句】
With his company doing bankrupt, he is now as poor as a church mouse.
随着他的公司倒闭破产，他目前已是一贫如洗。

When I last saw him, he was as poor as a church mouse.
我上次见到他的时候，他已经一贫如洗了。