树叶在微风中轻轻颤动。

The leaves ___flutter gently in the breeze.

每次上台演讲前，我的心都会因为紧张而狂跳不止。

My heart ___flutters every time before I give a public speech.

旗帜在微风中轻轻飘动。

The flag ___fluttered gently in the breeze.

考试前她总是感到一阵心慌。

She always gets into a ___flutter before exams.