Lesson 4 An exciting trip课⽂内容：
I have just received a letter from my brother, Tim. He is in Australia. He has been there for six months. Tim is an engineer. Heis working for a big firm and he has already visited a great number of different places in Australia. He has just bought an
Australian car and has gone to Alice Springs, a small town in the centre of Australia. He will soon visit Darwin From there, hewill fly to Perth. My brother has never been abroad before, so he is finding this trip very exciting.本⽂语法：同位语
语法归纳：指同⼀事物的句⼦成分放在同等位置时，⼀个句⼦成分可被⽤来说明或解释另⼀个句⼦成分，后者称之为前者的同位语。同位语多由名词或代词充当。例如：
I have two sisters,Jane and Mary.我有两个姐姐，简和玛丽。
This is Tom, president of Oriental Grouop.这位是东⽅集团的总裁汤姆。精讲笔记：
1.I have just received a letter from my brother, Tim.我刚收到⼀封弟弟蒂姆写来的的信。
语⾔点1 短语：receive sth. from sb.收到从某⼈那⾥送出的某物
This morning I received a letter from my brother.今天早上我收到了妈妈写来的⼀封信。语⾔点2 此句中Tim为my brother的同位语，对my brother进⾏解释说明。2.He is in Australia.他在澳⼤利亚。
语⾔点 介词in在此实际上表达⼀种状态：在澳洲。
类似介词⽤法：at home在家；on the Internet在上；on the phone打电话3.He has been there for six months.他在澳洲已经待了六个⽉了。
语⾔点 for six months是表⽰时间段的状语。
特别提醒初学者：\"for+时间状语\"不能和瞬间性动词连⽤。He arrived there for six months.（错误）He has been there for six months.（正确）
原因：瞬间动词的动词不可以延续，⽽be there表⽰状态，可以延续。
So far, I have lived in Beijing for eight years.到现在，我已经在北京住了8年了。
