enlarges on

Throughout the novel, Dickens enlarges on this theme, describing slums so decrepit that whole rows of houses are on the point of ruin.

整个小说，狄更斯扩大这个主题，描述贫民窟，使整个排破旧的房屋都在点毁掉。

The writer enlarges on the point.

作者详述那一点。