tremor|tremors

她在演讲前感到一阵紧张。

She felt a ___tremor of nervousness before her speech.

昨晚我们感觉到几次轻微的地面震动。

We felt several small ___tremors last night.

他的手因为紧张而微微颤抖。

There was a slight ___tremor in his hands due to nervousness.