close: applies to something made up of separate items that are or seem pressed together: paintings hung ~ together.    close作形容词表示近near，引申为紧密密切仔细等， 如"closely unite around the CPC Central Committee with Comrade Xi Jinping as the core紧密团结在以习近平同志为核心的党中央周围"摘自新华社2016年10月29日一篇报道，又如take a close look at 仔细看看on closer examination仔细查看/pay close attention密切注意，都来自close作形容词表示近near


dense: implies compression of parts or elements so close as to be almost impenetrable: the ~ growth in a tropical rain forest.    （dense有3个意思  1、密集稠密containing a lot of things in small area，如a dense crowd/forest密集的人群/密林，如areas of dense population人口稠密地区     2、浓密浓重的difficult to see through，如dense fog/smoke/fumes浓雾/烟/浓烈的气体   3、物理学表示密度大heavy in relation to volume，如less dense substances move upwards密度小的物质向上浮动，如a small dense star密度大的小恒星；density是物理中的密度: the mass of a solid, liquid or gas per unit of its volume固体、液体或气体单位体积的质量, mass除表示质量，还表示同种物质大量聚集）       compress压缩


compact: suggests a firm, neat union or effective consolidation of parts within a small compass: a ~, muscular body. (compact有3个意思 1、小型袖珍smaller than other things of the same kind，如a compact camera/car/design小型(袖珍)相机/小型车/袖珍设计  2、密实夯实something is pressed and harder and fills less space，可以作形容词或动词，如compact(ed) soil/dirt/snow/disc夯实的土灰雪/CD(光碟光盘)  3、身体短小结实short but solid and strong，如a compact body身体结实，如a compactly built hockey player身体结实的曲棍球运动员；另外compact可以单用，表示1、小型车a small car 2、女式化妆盒a small flat case containing makeup for a woman's face 3、正式协议a formal agreement） firm坚硬  consolidation使坚硬  （neat整齐整洁implies clearness from dirt, clutter, or admixture不脏不乱，如neat workmanship工整的工艺，还可表示娇小玲珑，如her neat figure她那娇小玲珑的身材）


thick: implies a concentrated condensed abundance of parts or units: a ~ head of hair.  （thick有2个意思 1、厚的肥的having a large distance between the top and bottom or front and back surfaces，如a thick book/wall/glasses/slices of break/wool sweater厚书/墙/眼镜/面包/毛衣，如he was thick around the middle他腰部肥胖  2、浓密的being closely together in a large amount，如thick fur/hair/gravy/syrup/sauce/fog/smoke/accent浓密的皮毛/头发/浓肉汁/糖浆/酱汁/雾/烟/浓重口音，如谚语blood is thicker than water血浓于水）  condense浓缩


close紧埃紧密密切: 表示间距小，好像"挤压"在一起(pressed together)，dense密集稠密: 指密度大到几乎无法穿透，compact紧凑结实、小型: 表示短小而密实，thick稠密浓密: 和dense同义，也表示密集稠密


记忆方法: 1）首字母CDCT想成稠稠的汤<==稠密          "密"从山从宓 mì，"宓"意为隐藏处，合起来表示"山中的隐蔽处"，如小空地小空间小缝隙。引申出2个意思： 1、隐蔽，即秘密，如机密密电 2、事物之间距离近，和疏相对，如稠密亲密密切密友。都和本义密切相关。      "紧"本义是"急速缠丝"，引申为1、不松弛 2、距离近，等于密      "稠"从禾周声，本义是"禾多而密"，如麦苗很稠人口稠密，还表示液体中固体成分多，如颜料太稠汤面太稠。    "浓"从水农声，本义是"露多"，特指液体或气体中所含某种成分多，与淡、薄相对，如浓茶血浓于水浓妆浓重情深意浓

         2）稠密的意思是紧凑mean massed tightly together.    mass在这里表示同种物质大量聚集