加些面粉让汤汁变稠。

Add some flour to ___thicken the soup.

随着调查的深入，案情变得越来越复杂。

As the investigation continues, the case ___thickens with new evidence.

随着剧情的发展，故事变得更加复杂和引人入胜。

The plot ___thickened as the story progressed, becoming more intricate and engaging.