sudden /ˈsʌdn/ I. adj.突然的，意外的：be caught in a sudden rain被突如其来的大雨淋了；a sudden turn in the road 路上的急转弯; sudden death 暴卒 ‖II. n. 只用于习语：all of a sudden/(all) on a sudden 突然，冷不防：All of a sudden the lights went out. 灯突然灭了。
suddenness n. 突然
suddenly /ˈsʌdnli/ adv.突然地，意外地 (= all of a sudden): Suddenly there came a knock at the door. 突然有人敲门。Her eyes suddenly filled with tears. 她突然热泪盈眶。
