dwell on something
phrasal verb with dwell verb [ I usually + adv/prep ] formal uk/dwel/ us/dwel/ dwelt or dwelled | dwelt or dwelled
C1 老是想着，一直在说（尤指不好或令人不快之事）
to keep thinking or talking about something, especially something bad or unpleasant
In his speech, he dwelt on the plight of the sick and the hungry. 演讲时他一直在说遭受疾病和饥饿折磨的人们所处的困境。