A．When young people(年輕人)know each other(互相)．

  B．When young people don't know each other．

  C．When a young person speaks to an adult(成年人)．

  D．When adults don’t know each other．

  E．A teacher and a student in the classroom．

1．—What’s this in English，Li Ming？　　　　 

    —It’s a pencil，Miss．

    一Good．Can you spell “pencil”，please?

    一P-E-N-C-I-L．

2．一Hi，Frankie! How are you today?　　　　 

    —I’m fine，thanks．And you?

    一I’m fine，too．

3．一Good morning，Mr．Rivers．  　　　　

    一Good morning，Ben．How are you today?

    一I’m fine．Thank you．

4．Greg，this is Charlie．　　　　 

    一Hi，Charlie! Nice to meet you．

一Hello．

5．—Miss Black, this is Mrs. Street.　　　　 

  —How do you do?

    —How do you do?