Dialogue（see Figure 2）

In this section，Mandarin dialogs are presented accompanied by English translations.When an initial utterance is selected，the learner is able to listen to it and provide a corresponding（predetermined）response.This is in fact a conversation between the computer and the learner.The program analyzes the learner's speech and then makes a decision either to accept or reject the utterance.If the computer accepts the speech，the learner is able to go to the next round of the conversation.Otherwise，the utterance has to be repeated until the program accepts it.