Unit 1 How can we become good learners?语法一.介词 by 的使用方法1.by 意为“通过”，其后常接名词或动词-ing 形式。用来表达“以、通过、用（某种措施或手段）”而达到某种预期的目的，常用来回答 how 引导的特殊疑问句。by doing sth 意为“通过做某事”—How does the boy improve his spoken English?—By talking with a foreigner. (1)—How do you learn English so well?— chatting with my uncle in America online.A. By B. With C. In D.And(2)Jackson studied Chinese by __________ tapes.A. listening B. to listen C. listening to D. to listening to 2.by+ 时间， 意为 “不迟于，在……之前 ”I have to go to bed by ten o’clock.3.by+ 地点， 意为 “在……旁 ”Jim sat down by the window.4.by+ 交通工具， 意为 “乘……” I go to school by bike.5.由 by 构成的固定短语：by the way 顺便说一下 by oneself 独自=alone二.目前完毕时的使用方法(一)使用方法:1.表达过去发生的某一动作或状态对目前导致的影响或成果.常用的标志词有already( “ 已经” , 用于肯定句 ),yet( “ 还 , 已经”，用于否认句和疑问 句 ),ever （ “ 曾 经 ” ） ,never （ “ 绝 不 ， 从 不 ” ） , just （ “ 刚 刚”） ,before （“此前”） ,once （“一次”） ,twice （“两次”） .I have already eaten the dinner.（阐明我目前饱了）。I have already seen the film.(1)You don’t need to describe her. I ______ her several times.A. meet B. will meet C. have met (2)—Hi,guys.Where are you heading(向……行进) now? —Home.We all our money,so we have to walk home now.A. spend B.spent C. have spent D.are spending(3)Have you ever seen him ________?A. ago B. two days ago C. before D. just now2.表达过去发生的某一动作或状态，一直持续到目前。常常与时间状语 for+时间段 ,since+ 时间点或一般过去时从句 , 如： for five minutes （ 5 分钟） since 1985 （自从 1985 年一直到目前） .since he was five years old（自从他是五岁的时候一直到目前）目前完毕时的标...
