他在钢琴上练习演奏这首赋格曲。

He is practicing playing this ___fugue on the piano.

她有时会陷入这种奇怪的状态，完全不记得自己是谁，甚至不记得自己是怎么来到这个地方的。

She sometimes enters these strange ___fugues, completely forgetting who she is or how she got to certain places.