flighty

她总是变换想法，这种轻浮的态度让人难以信任。

Her ___flighty nature makes it hard to trust her decisions.

她那轻快的脚步像小鸟一样在人群中穿梭。

Her ___flighty footsteps darted through the crowd like a little bird.

他太过善变，昨天还对绘画充满热情，今天又迷上了摄影。

He's too ___flighty, passionate about painting yesterday but obsessed with photography today.