When you are little, the whole world feels like a big playground．I was living in Conyers, Georgia the summer it all happened．I was a second grader, but my best friend Stephanie was only in the first grade．Both of our parents were at work and most of the time they let us go our own way．
It was a hot afternoon and we decided to have an adventure in Stephanie' s basement．As I opened the basement door, before us lay the biggest room, full of amazing things like guns, dolls, and old clothes．I ran downstairs,and spotted a red steel can．It was paint．I looked beyond it and there lay even more paint in bright colors like purple, orange, blue and green．
"Stephanie, I just found us a project for the day．Get some paintbrushes．We are fixing to paint．"She screamed with excitement as I told her of my secret plans and immediately we got to work．We gathered all the brushes we could find and moved all of our materials to my yard．There on the road in
front of my house, we painted bit stripes(条纹) of colors across the pavement(人行道)．Stripe by stripe,our colors turned into a beautiful rainbow．It was fantastic!
The sun was starting to sink．I saw a car in the distance and jumped up as I recognized the car．It was my mother．I couldn' t wait to show her my masterpiece．The car pulled slowly into the driveway and from the look on my mother' s face, I could tell that I was in deep trouble．
My mother shut the car door and walked towards me．Her eyes glaring, she shouted, " What in the world were you thinking? I understood when you made castles out of leaves, and climbed the neighbors' trees, but this ! Come inside right now !" I stood there glaring back at her for a minute, angry because she had insulted(侮辱) my art．
"Now go to clean it up!" Mother and I began cleaning the road．Tears ran down my cheeks as I saw my beautiful rainbow turn into black cement．
Though years have now passed, ! still wonder where my rainbow has gone．I wonder if, maybe when I get older, I can find my rainbow and never have to brush it away．I guess we all need sort of rainbow to brighten our lives from time to time and to keep our hopes and dreams colorful．
It can be learned from the passage that parents should_______．
推理判断题。从文章开头叙述作者开心地画彩虹的过程，到后来被妈妈要求把街道清洗干净，再到最后的感慨，作者最终想要表达的观点之一是：父母应该支持孩子的某些创造性行为，而不是一味地否定。
把10gMgCl2和MgSO4的混合物溶于适量水中，滴加2mol／L的BaCl2溶液至沉淀完全，共消耗BaCl2溶液25mL。求混合物中MgCl2和MgSO4的质量各是多少克
固定在匀强磁场中的正方形导线框abcd，各边长为1．其中ab是一段电阻为R的均匀电阻丝，其余3边均为电阻可忽略的铜线。磁场的磁感应强度为B，方向垂直纸面向里。现有一与ab段的材料、粗细、长度都相同的电阻丝PQ架在导体框上，如图所示。PQ以恒定速度方向如何
一小物块以速度v0=10m／s沿光滑地面滑行，然后沿光滑曲面上升到顶部水平的高台上，并由高台上飞出，如图所示。问当高台的高度h多大时，小物块飞行的水平距离最大这个距离是多少(g=10m／s2)
某晶体盐的水溶液呈浅绿色，在此溶液中通入氯气，溶液变为棕黄色，把所得棕黄色溶液分成两份：一份加入KSCN溶液，溶液变深红色；另一份加入BaCl2溶液，产生不溶于稀HNO3的白色沉淀，则该晶体盐的化学式是_______。
欲除去乙烷中的乙烯，可将混合气体通过盛有_______的洗气瓶；欲除去乙炔中的硫化氢，可将混合气体通过盛有_______的洗气瓶。
浓硝酸常盛装在棕色瓶中，且贮放在冷暗处，原因是_______，
碳酸氢钠溶液和烧碱溶液反应的离子方程式为_______。
常温下，氨水中存在的离子有_______。
在酸或碱存在的条件下，甲酸甲酯跟水发生水解反应的化学方程式为_______。
有下列几种气体：H2、O2、HCl、NO、NH3、CH4，其中通常情况下能用来和水做“喷泉”实验的是_______。
