sudden的adv形式

sudden的副词形式是suddenly，意思是adv. 忽然；突然地

它的用法是

The geographer was suddenly stirred to excitement.

地理学家忽然激动起来。

哈利波特与密室

Dobby suddenly froze, his bat ears quivering.

多比突然僵住了，两只蝙蝠状的耳朵颤抖着。