n(1)云((variously-shaped weightless mass of)water vapour floating high in the sky)[C，U]：The black～s soon cleared away.乌云很快飘散了。white/grey～s in the sky空中的白云/乌云;The top of the mountain was covered in/hidden under～.山顶笼罩/遮蔽在云中。

(2)烟(尘)雾(variously-shaped weightless mass of dust，smoke，sand，etc，floating in the sky)[C]：The motor-car raised a～of dust.汽车扬起一阵灰尘。C～s of smoke rose above the bombed city.被轰炸的城市上空升起团团烟雾。

(3)大群(团)(large moving mass of insects in the air that appears to resemble a could)[C]：a～of insects/flies/mosquitoes/locusts一大群昆虫/苍蝇/蚊子/蝗虫;〖同〗swarm;

(4)混浊(之处)((an area of) darkness in a liquid or on a transparent object)[C，U]：There was a/some～in the bottom of the beer. 底部的啤酒有点混浊。

(5)引起不幸(恐惧，疑惑，忧郁)的事物;阴影(thing that causes unhappiness，fear，depression，uncertainty，etc)[C](fig)：a～of suspicion/gloom/sadness怀疑/忧郁/悲伤的阴影;The～s of war are gathering.战争的阴云越来越密集。the gathering～s of revolution 越来越浓重的变革阴影;(sth) cast～of gloom over a party给聚会投下了一层忧郁的阴影;under～受怀疑，失体面;

→′cloudless adj 无云的;′cloudy adj 多云的;阴的;混浊不清的;不明确的;′cloudburst n 大暴雨;′cloud-bank n 低而密的云团;

v (1)(使)遮蔽((cause to) become covered with or as if with clouds)[T+n，I+adv(over)]：The sun is～ed.太阳让云遮住了。The sunny sky suddenly～ed over. 晴朗的天空突然乌云密布。Fog/Mist～ed the mountain tops.雾/薄雾遮住了山顶。Exhaust fumes～ed the air. 废气在空气中弥漫。〖同〗darken，dim;cover，veil;〖反〗clear，uncloud;uncover，unveil;

(2)(使)混浊(朦胧)((cause to) become dull，unclear，indistinct or less transparent)[I，T+n]：His eyes～ed with tears.他泪眼朦胧。(tears)～sb's eyes(眼泪)使某人的眼睛朦胧起来;(steam)～the window(蒸气)使窗户蒙上一层雾气;She lit a cigarette and soon～ed the room in smoke.她点着一根香烟，很快就使房间变得烟雾弥漫了。

(3)使不清楚(混乱)(make unclear，uncertain，confused，etc)[T+n]：Age～ed his memory. 他上了年纪，记忆不清。His love for her～ed his judgement.他对她的爱使他判断不明。Superstition～ed their thinking.迷信使他们的思维迷乱。Her explanation～ed the issue. 她的解释把问题搞糊涂了。〖同〗confuse;〖反〗clear，clarify;

(4)显得忧郁((of sb's face)show sadness or worry)[I，I+adv(over)]：His face/brow～ed with anger. 他满面怒容。His face～ed (over) at the unhappy news/at the mention of that.一听到那不幸的消息/一提起那事他的脸就阴沉下来了。

(5)给……投下阴影(spoil(sth);threaten)[T+n]：The accident～ed his reputation.那次事故损害了他的名誉。(accident)～sb's enjoyment/happiness/friendship(事故)给某人的欢乐/幸福/友谊投下阴影