The passage twisted and turned, moving down all the time, and the water gradually deepened.

These columns, colored pink below and gradually deepening in color to red near the top, have a corrugated surface texture.

They deepen gradually in the summer months depending on the temperature variance.

The water deepened gradually as he went on.

But the water gradually deepens as you go forward, and the pool ends in a deep pot under each bank.

The dusk gradually deepened and the shades of evening closed in, but Mimi did not seem to notice or to care.

They traveled for a while in silence as late afternoon twilight gradually deepened into evening.

Over the next few days, the low pressure area gradually deepened as it drifted north-northeastward.

She had always felt that liking should come first then gradually deepen into love.

Our co-operation gradually deepened, especially in the last two years, so that the united authorship of a book became a possibility and an achievement.