为了比较甲、乙、丙三种微生物所产生的淀粉酶的活性，某生物兴趣小组以三种微生物提取液（提取液中淀粉酶浓度相同）为材料进行了如下实验．

图中的两条光线是由同一点光源S发出经平面镜反射后形成的，请完成光路图并确定光源S的位置．

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Zhang Shiyuan 13

    I am very interested in all kinds of dramas,espccially those by William Shakespeare.But it is impossible to watch stage(舞台) drams every week.So my small goal is to watchat least one movie online from Shakespear's works,It will not only improve my English,but also help me have my own taste in drama.
Wu Qianhui,14

    For me,the small goal is to run 300 meters everyday. It isn't an easy thing,especially to do it everyday.But I will not shy away from the challenge.I have the confidence(自信)to make it.  I believe I can hold on and achieve my goal.

Gu Jiayi,13

    My goal is to master a skill like cooking. It is not very difficult,but it takes a lot of time.So I'll make myself leam how to cook during holidays.The aim will help me make gooduse of time and be more independent.

Zhen Yishi,14

    I want to finish reading two English novels this year .Reading plays an important role in my lile. It will not only improve my English reading and witing skill,but also enlarge my scope of kowledge in many felds.It is not a big goal.But to achieve this goal I need patience and persistence(坚持).

Shen Botao,14

    My present small goal is to pass the piano grade exam.When I was in Primay school, I began to learn to play the piano. I not only took a great interest in music, but also relaxed myself. I want to play the piano better. I think I can make it by the end of this term.

逆反心理是指人们彼此之间为了维护自尊，而对对方的要求采取相反的态度和言行的一种心理状态。孩子到十二三岁的时候，往往产生一种与父母相抵触的情绪。他们心里有什么话也不愿向父母说，对于父母的批评和劝导不像以前那样听话了，甚至产生抵触情绪。人们把孩子的这种现象称为逆反心理。

逆反心理的表现是多种多样的。如对教育者有明显的“反控制”、“对抗心理”，即你要求我这样，我偏不这样。而这种情形，最容易引起老师、父母的恼火。而老师、父母越是恼火，他（她）就会更加反感，直接影响到与父母、老师之间的正常关系。