新概念2册L16笔记（条件状语从句if、unless、as long as、双重否定）

L16 Apolite request

本课单词和课文注释
  park v.
  
  traffic n. 交通；行驶的车辆（不可数）
    there's always a lot of traffic at this time of day #每天这个时候路上总是车很多
  
  ticket n.
  
  note n.
    leave a note for sb #给某人留便条
    
  area n.
    parking area  
    
  sign n. 指示牌
    a road/traffic sign 路标
    The sign on the wall said 'Now wash your hands'  #墙上的牌子写着“请洗手”
    Headaches may be a sign of stress #头疼可能是紧张的迹象
 
  reminder n. 提示  remind pred.
    The incident served as a reminder of just how dangerous mountaineering can be #事故提醒人马登山运动会有多么危险
  
  fail v. 无视、忘记、失败
    fail in sth
      I failed in my attmpt to persuade her
    fail to do #如果要表动作
      She failed to get into art college
    
  obey v.
    obey a command  / obey an order
    
  课文第一句即为主将从现，if引导的为从句，逗号后分隔的为主句，且为将来时
    if you park your car in the wrong place,a traffice policeman will soon find it
  
  课文第二句亦为主将从现，if放在句尾无需逗号分隔
    You will be very lucky if he lets you go without a ticket
  
  课文第四句police和people同为复数形式，be需要变形。如果想说一个警察，policeman
    Traffic police are sometimes very polite 
  
  课文最后一句cannot fail都有否定的意思构成不得不，比must更强烈
    If you receive a request like this,you cannot fail（双重否定） to obey it
  
  英文中第二人称you由“任何人”的意思

条件状语从句

本章重点:if #条件状语从句，看到if它就是从句一般都用现在时
归纳：主将从现，主句可以用将来时表未来可能发生什么，从句为了确立这个条件，一般都用现在时（陈述客观事实）

  if条件状语分类：主将从现、主情从现、主祈从现(动原型)；位置上有主语if或者从句if
  1、if...,（注意此处有逗号）主语+will do...  #条件从句如果if位于句首从句需要以逗号分隔    
    主情从现：
    If winter comes,can（情态动词） spring be fa behind?  #如果冬天都来了，春天还会远吗
  2、主语+will do...if      #条件从句如果if位于句尾省略逗号 
    主将从现：
    I will（将来时） play football with you tomorrow if my mom isn't at home
    
  其他条件连词
    unless  除非
      These skills will be useless unless you caryy them out
    as long as 只要
      As long as you work hard enough,an iron rod can be ground into a needle  #只要功夫深，铁杵磨成针

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