蓬松的白云飘过天空。

Fluffy white clouds were ___floating across the sky.

钢琴声从敞开的窗户飘出。

The sound of piano-playing ___floated out through the open window.

突然，我看到一个'东西'在窗户旁漂浮，发出声音，不像人类。

Suddenly, I saw a "thing" ___floating by the window, making noises and like nothing human.