delay: implies a holding back, usually by interference, from completion or arrival: bad weather ~ed our return.  另见2018-05-09 拖延delay-dally       （hold back阻挡阻碍to prevent or restrict the advance or progress or development of something，如he was so impatient that I could hardly hold him back他那么急躁, 我简直拉不住他，如they built dykes and dam to hold back the rising flood waters他们修筑了堤坝来阻挡上涨的洪水）


retard: applies chiefly to motion and suggests a slowing, often by interference: language barriers ~ed their rate of learning.


slow: often used with up or down, also implies a reduction of speed, often with deliberate intention: the engineer ~ed the train.


slacken: suggests an easing up or relaxing of power or effort: he needs to ~ his pace if he intends to finish the race.


detain: implies a holding back beyond a reasonable or appointed time, often with resulting delay: unexpected business had ~ her.


delay延迟耽误: 指干扰其完成到达，retard阻碍: 指动作受干扰而变慢，slow减速: 和up down联用，指有意减速，slacken放缓: 表示减小用力，detain超期停留、拘留: 指超出合理预定时间，即延迟


记忆方法: 1）首字母DRSSD想成穿衣DRESS，需用D替换E<==减缓    "缓"作形容词时表示"慢"，与"急"相对，例缓步缓行缓和；作动词时表示"延迟延期"，如缓刑迟缓，如<孟子·滕文公上>:"民事不可缓也"；本意是"放宽衣带"使从容自在，如缓带缓服，现很少用。都会导致本组cause to be late or behind迟到落后

         2）减缓的意思使减速延期mean to cause to be late or behind in movement or progress.