未知题型 It is stated in Paragraph 1 that the theory of relativityA．is beyond all the current scientists' understanding.B．has failed Albert Einstein for years.C．seems at odds with the quantum mechanics.D．is useful in holding big things together.

未知题型 Douglas Gentiles research tends to testA．whether video games can produce long-term impact on the youth.B．the effect of playing pro-social games on the youth.C．whether the youth are able to classify different video games.D．the effect of playing violent games on the youth's moral fabric.

单项选择题 你在平常的跳远练习时最多只能跳到4.8米，而你在参加运动会时却跳到了5米。这体现了当个人与其他人一起工作时，由于他人在场而激发了自己的工作动机，由此引发绩效水平提高的倾向，这一现象属于群体内互动的( )。A、协同效应B、社会促进效应C、社会致弱效应D、社会标准化效应