He is as poor as a church mouse.

他一贫如洗。

《新英汉大辞典》

Although very rich in his youth, he is now as poor as a church mouse.

虽然年轻时很有钱，他现在穷得像教堂的老鼠。

youdao

When you are poor, home is a nest, even if it is as poor as a church mouse, it can still keep out wind and rain.

当你贫穷的时候，家是一个窝，即便是穷徒四壁，仍然可以遮风挡雨。

youdao