If you speak a language or read fluently, you speak or read easily, well, and quickly

I'd like to speak English fluently. 我希望能说一口流利的英语。

Students are expected to read fluently in Arabic. 学生应能流利地阅读阿拉伯语。

in a way that flows smoothly

The dancers move fluently across the stage. 舞蹈演员在舞台上优美地移动。

We passed the ball fluently and were in full control of the game. 我们流畅地传球，完全控制了比赛。