Operation MigrationIf you look up at the sky in the early fall in the northern part of North America, you may see groups of birds. These birds are fly...
名词：(一)英语名词可分专有名词和普通名词两大类：1.专有名词是个别的人、地、物、团体、机构等的专用名称。专有名词中实词的第一个字母要大写。如：Beijing, Tom, the People’s Republic of China(中华人民共和国)专有名词如果是含有普通名词的短语,则必须使用定冠词...
add up to合计，总计break away(from)脱离，逃跑come true实现，达到come up with提出，提供do away with废除，去掉have nothing to do with和…毫无关系make believe假装catch up with追上，赶上come u...
be able to(do)能(做)，会(做)be absent from缺勤，缺课be accustomed to习惯于be active in积极于be alive to发觉，感觉，对…敏感be angry with对……发怒be anxious for急切盼望，渴望be about to(do...
and so on等等all at once突然;同时，一起once(and)for all一劳永逸，限此一次by oneself独自地，单独地other than不同于all right好，行ever since从那时起，自那时以来ever so非常，极其so…as to结果是;如此……以至于at...
once upon a time从前no wonder难怪，怪不得decline with thanks婉言谢绝account for说明(原因等)allow for考虑到arrive at达成，得出ask for请求，要求begin with从开始break off断绝，结束break up中止，...
Lead PollutionLead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions ori...