2.　　 Play the recording .Write “when” or “while” on each line .

1.　　 Read the instructions .

3.　　 Play the tape again ,correct the answers .

SB Page 19 , 2b .

2.　　 Play the tape twice .Order these statements .

1.　　 Read the sentences .Make sure the Ss understand what they mean .

4.　　 Check the answers .

Step 4 　Post-task

Talk about what people were doing when the UFO arrived .

Step 5　 While-task

SB Page 19 , 2a .

3.　　 Play the tape twice . Circle the correct responses .

2.　　 Look at the dialogue in the picture .

Explain :

过去进行时态的构成: was / were + doing　 .

用法:表示过去某一时刻或某一段时间正在进行的动作，一般用时间状语来表示。

I was standing in front of the library when the UFO arrived .

1.　　 Read the instructions .Make sure the Ss understand what they should do .

4.　　 Practice reading .

Step 3　 While-task

SB Page 18 , 1b .