[00:00.00]
[00:00.73]Unit 2 Mr Li was a teacher. 
[00:06.66]Ò»¡¢Listen and tick. ÌýÒ»Ìý£¬¹´Ò»¹´¡£
[00:16.59]1. M: study hard   
[00:24.74]2. W: teach Maths  
[00:31.56]3. M: go to school   
[00:38.70]4. W: twenty years ago