[ti:UNIT 3 Having Fun in Beijing Lesson 20] [0:01.721]UNIT 3 [0:04.162]Having Fun in Beijing [0:07.683]Lesson 20: [0:10.404]Let's Write Home [0:14.107]Li Ming's letter 李明的信 [0:17.157]Thursday, February 4th 星期四,2月4日 [0:20.000]Dear...