He dwelt on the pleasure of the past.
He dwelt on the complexities of modern life.
She dwelt on the miserable days she spent there.
He dwelt on an unpleasant subject for two hours.
Our teacher dwelt on the importance of punctuality.
The Prime Minister dwelt upon the financial crisis.
In his speech he dwelt on the importance of education.
The lecturer dwelt on some memories of his college days.