rainbaobao1116
首先这几个词共同的root是tain=hold, keep, have以下几个prefix:re = back,againob,oc,of,op = toward,against,in the waysub, suc, suf, sup, sur, sus = under,below,from, secretly, instead ofco, cog, col, coll, con, com, cor = with,together那么现在来看retain的意思是保留，持有，继续拥有。强调的是这种拥有是持续性的，反复性的。to keep something; to continue to have something obtain的意思是获得，赢得。强调的是通过努力得来的。to get something, especially by making an effortsustain的意思是维持，支撑，承受。强调的是维系。一般承受这种压力的主体都是在下面默默的承受。to make something continue for some time without becoming less contain的意思是包含，容纳，含有的意思，就是把东西聚集到一起拥有。if something contains something else, it has that thing inside it or as part of it.这样我觉得是比较正确的理解方法。
栤菊粅雨
sustain --keep sb./sth.alive or in existence（支持、维持生命）, to keep up the strength, spirits or determination of （维持体力/精神/决心）如：The supplies of food were scarcely enough to sustain life.食品的供应仅够勉强维持生命。A light meal won't sustain us through the day.一顿小食维持不了我们一天的精力。Hopes alone sustained him in his misery.他在痛苦之中只有希望鼓励着他。现代英语中也有互用的情况。 如：我们也看到“enough food to maintain one's stength”这样的句子。这时maintain =sustain .
霸州楚楚吊顶
表示支持的有这样一些单词短语：sustain V.是{某人，某事}维持例：A good breakfast will sustain us through the daysupport v.支持{某人的观点}例：Do you support the union's demand for higher wages?stay by 也可以，用法差不多永远支持你可以这样翻译I will support you forever
