v (1)1) 跳(跃)入(水中) (throw oneself head first down (into water) suddenly) [I+prep(into)， I+adv(in)]：～into water/the sea/the swimming pool 跳入水/海/游泳池中;They ran to the lake and～d in. 他们跑到湖边，跃入水中。The best way to start a swim is to～in. 开始游泳的最好方法是跳入水中。〖同〗dive，jump，leap; 〖反〗rise; 2)使伸(插，刺，突)入 (cause to enter sth suddenly and forcefully) [T+n+prep(into)， T+n+adv(in)]：～one's hand into cold water/a piece of cloth into a pail/a red-hot horseshoe into a bucket of water 把手伸入冷水中/一块布投入桶中/烧红的马蹄铁放入一桶水中蘸一下;～one's hands into one's pockets/a pitchfork into the hay/a rod into a blocked drain 把手插在衣服口袋里/一把草叉插入干草堆/用一根棍子去捅堵塞的下水道;～a sword/a dagger/a knife into sb's heart/breast 把剑/匕首/刀刺入某人的心脏/胸膛;～a sword/a knife in 把剑/刀刺进去;〖同〗thrust; 3)(使)陷入(某种情况或状态) ((cause to) enter a certain state or condition suddenly) [I+prep(into)， I+adv(in)， T+n+prep(into)， T+n+adv(in)]： The country/company～d deep into debt. 这个国家/公司深深陷入债务之中。He～d into thought/his work. 他陷入沉思/投身于工作之中。The country (was)～d into civil war/open conflict with its neighbours. 这个国家卷入内战/与邻国的公开冲突之中。(news)～sb into despair (消息)使某人陷入绝望;(extravagant life-style)～sb into debt (奢侈的生活方式)使某人陷入债务之中;(event)～the world/a nation into a new war (事件)使世界/一个国家陷入一场新的战争;～society into chaos/anarchy 使社会陷入动乱/无政府状态;They were～d into civil war/an economic crisis. 他们陷入了内战/一场经济危机。The room/hall was～d into darkness. 房间/大厅陷入一片黑暗之中。4) (突然)开始 (enter into an activity suddenly or hastily) [I+prep(into)， I+adv(in)]：～into a description of one's illness 突然讲起自己的病情;～bravely into a debate 突然勇敢地投入辩论;He～d in and gave his opinion. 他突然插话，说出了自己的看法。

(2) 1)(使)突然向前(下)冲，(使)猛冲(急降) ((cause to) move suddenly and quickly forwards and/or downwards) [I， I+prep， I+adv， T+n+prep， T+n+adv]： The horse suddenly～d and threw its rider forward. 马突然低头，把骑手从前面甩了下去。Sales/Prices/Share prices have～d (by 20%). 销售/物价/股票价格急剧下跌(20%)。The temperature～d lower than normal. 温度陡降至正常水平以下。(elephant)～into the forest大象钻入树林;(thief)～into the crowd (小偷)钻进人群;(fireman)～into the building(消防队员)冲入大楼;The river～d into the gorge. 河床陡降进山谷。～through the undergrowth/over the cliff 钻进矮树丛/猛地翻下悬崖;The rope broke， and the elevator～d to the ground. 绳子断了，电梯一下子落到地上。The road～d here/towards the beach. 这条路在这里/向海边陡降。The bus suddenly stopped and she～d forward. 公共汽车忽然刹车，她猛地朝前一扑。The sudden jolt/stopping of the bus～d her forwards. 公共汽车的忽然颠簸/刹车使她猛然朝前一扑。〖同〗rush，dash，run;〖反〗crawl; 2) (船)颠簸 ((of a ship) move with the forward end going violently up and down in the water) [I]： The boat/ship～d in the storm/high seas. 船在暴风雨/波涛中颠簸。〖同〗pitch，toss，rock;

n (1)跳(跃)入 (水中) (act of throwing oneself head first down into water suddenly) [C]： a～into the water from the boat/sea from the rocks 从船上跳入水中/岩石上跳进海里;take a～into the pool 跳入水池中;a refreshing～in the lake 在令人神清气爽的湖中游泳;an early morning～清晨游泳;rely on the～into icy waters to kill sb 指望把某人扔进冰水中来杀死他;〖同〗dive，jump，leap;

(2)陷入，急跌(sudden and steep fall) [C， 尤sing]：～into debt/chaos/crisis/poverty/danger 陷入债务/动乱/危机/贫困/险境;～into work 投入工作之中;Prices started a downward～. 物价开始急剧下跌。 The sky-diver had a～of 15，000 feet before the parachute opened. 花样跳伞运动员下落了15，000英尺后降落伞才打开。〖同〗drop，fall;

take the plunge (经过深思熟虑后)毅然采取行动： take the～and get married/start one's own firm 毅然决定结婚/开办自己的公司;

→′plunger n 投入(跳水)者;(清理堵塞下水道用的)木柄橡胶搋子;

【辨异】plunge与dip和immerse的区别见DIP。