【正确答案】The first difference lies in how the two dialogues are organized. The structure of dialogue 1 is a question-answer-question-answer one, while that of dialogue 2 follows a question- question-answer-answer pattern. According to Harvey Sacks, the basic unit of the conversation is the "turn", that is, a shift in the direction of the speaking flow. Conversationalists do not speak all at the same time: they wait for their "turn". In dialogue 1, Speaker A always takes the active talking turn in the communication and B follows A's way. Speaker A uses an indirect question instead of asking B directly. After making sure that B is free, A goes on to ask B whether he/she would like to go with him/her. Then B gives A the expected answer. While in dialogue 2, the structuring sequence is different. Instead of employing an indirect question, A asks directly whether B would like to go with him/her. Instead of giving a direct answer to A's question, B asks "for what". In such a case, A's active turn is changed into a passive one and B becomes the active role in the communication. So when A gives the answer, B refuses to go with him/her.

【答案解析】[解析] 本题可以结合句法学、语法以及语用学知识来回答，哪一种知识都无法单独提供合理的解释。这就要求考生具有很好的综合运用所学知识的能力，对语言学中所涉及的各分支学科知识能灵活运用，融会贯通。