人类的语言能力是从简单的咕哝声逐渐发展而来的。

Human language ability ___evolved from simple grunts over time.

鸟类是从恐龙经过数百万年进化而来的。

Birds ___evolved from dinosaurs over millions of years.

随着研究的深入，我们的理论逐渐发展成熟。

Our theory ___evolved gradually as the research progressed.