27. Scientific Theories In science, a theory is a reasonable explanation of observed events that are related. A theory often involves an imaginary model that helps scientists picture the way an observed event could be produced. A good example of thi

发表于:2018-12-08 / 阅读(333) / 评论(0) 分类 新概念优美背诵短文50篇

Pre-Listening Vocabulary device: a piece of equipment nautical: related to shipping or boating rival: a person that one is often in competition with side: to choose one person or argument to agree with etiquette: manners; proper behaviour and languag

发表于:2018-12-19 / 阅读(52) / 评论(0) 分类 Facts-事实

Pre-Listening Vocabulary regulation: related to a rule or standard (e.g., not including overtime) quarter: a period of play that lasts one-fourth of the whole time play: a single period of action or an important movement during a game replay: a recor

发表于:2018-12-19 / 阅读(49) / 评论(0) 分类 Facts-事实