My name is Cathy. I'm a fourteen-year-old girl from England. Now I'm 1 in a middle school.I have to say that I was not good 2 my lessons before. So I was always afraid of exams.

    Last week I 3 my end-of-year exams. Today I got my report card. 4 ， I did very well. My mom and dad said it was the best report. It was 5 main subjects that the report card talked about， and I felt very 6 today. My teachers ticked( 给…打勾 ) “7 to improve”，“Good” or “Very good”. My English teacher said my English was much better. For math and science I also 8 “ Very good” ticks. All my teachers said I was 9 And at the end of the report card my head teacher said， “A very good 10. Well done!” I am so pleased with it，but I hope I can get a better report next year. I'm sure I can.

小明用细铁丝、棉线、肥皂水等探究分子之间相互作用力，过程和方法如图用细铁丝做成一个圈，中间松松地系上一根小细棉线，如图甲所示．

（2）在肥皂水中浸一浸使肥皂水留在上面，如图乙所示．

（3）用手指轻轻地碰一下棉线一边的肥皂膜，（如图丙所示）猜一猜会出现什么现象， ____．通过这个实验你可以得到什么结论： ____

（4）小明还做了如图丁所示实验，上瓶内装有空气，下瓶内装有红棕色的二氧化氮气体（密度比空气大），将上下两瓶间的玻璃片抽掉，过一段时间后，两瓶气体混合在一起，颜色变均匀．这个现象说明 ____