C．Subjective involvement doesn't motivate smiling in social interactions.

　　D．Witchel's study finding is consistent with behavioural ecology theory.

　　D　[推理判断题。根据第四段尾句"Our study showed that in these human­computer interaction experiments，smiling isn't driven by happiness；it is associated with subjective involvement(主观参与)，which acts like a social fuel for smiling，even when socialising with a computer on your own"可知，试验结果表明，微笑不是由快乐驱动的；它与主观参与有关；结合第四段第二句"However，behavioural ecology theory suggests that all smiles are tools used in social interactions，meaning cheerfulness is neither necessary nor rich for smiling"可知，行为生态学理论认为，所有的微笑都是社会交往中使用的工具，这意味着快乐对微笑来说既不是必要的，也不是丰富的。据此可以推断，研究的结果与行为生态学理论一致，故D项正确。]

　　3．What do we know about the text?

　　A．Participants were asked to interact with each other in the quiz.

　　B．Participants in the quiz smiled less often when they got the answer wrong.

　　C．In Dr Witchel's opinion，smiling is connected with subjective involvement.

　　D．Dr Witchel thinks that a real smile reflects the inner state of cheerfulness.

　　C　[细节理解题。根据第四段尾句"Our study showed that in these human­computer interaction experiments，smiling isn't driven by happiness；it is associated with subjective involvement(主观参与)，which acts like a social fuel for smiling，even when socialising with a computer on your own"可知，Witchel博士认为，微笑不是由快乐驱动的，它与主观参与有关。故C项正确。]

　　4．What can be a suitable title for the text?

　　A．What Contributes to Real Happiness?

B．How to Identify Whether a Person Is Really Happy?