题目

实验室有一瓶化肥的标签已脱落，只知道它是NH4Cl、(NH4)2SO4、NH4HCO3和尿素[CO(NH2)2]中的一种。请你完成以下探究： 【猜想】猜想①：该化肥是NH4Cl，    猜想②：该化肥是(NH4)2SO4         猜想③：该化肥是NH4HCO3， 猜想④：该化肥是尿素。 【实验探究】 （1）取少量样品在研钵中与熟石灰研磨，有剌激性气味的气体放出，证明猜想      不成立；写出其他任一猜想发生反应的化学方程式：      。 （2）如上（图1），另取少量样品于试管中，滴When I was in Grad e 3 in primary school, I was chosen to be the princess in a school play. I could say my lines ____ at home, but as soon as I was on the stage, every word ____ my mind. Finally, my teacher had to ask me to change my __.I became a narrator. (解怳员) I didn't tell my mother what had happened when went home for lunch that day.__ she sensed my unhappiness and asked___ I wanted to take a walk in the yard. It was a lovely spring day. My mother bent down for some dandelions."I think I'm going to dig up all these weeds, "she said."From now on, we'll have only roses in the garden." "But I like dandelions, (蒲公英) I said."All flowers are beautiful---___dandelions." My mother looked at me seriously."Yes, every flower is beautiful, isn't it?"sheasked. I __,"And that is true of people too,"she added."Not____can be a princess, but it's not a shame." She had sensed my pain. I started __ and told her what had happened. She listened and smiled. "But you will be a beautiful narrator," she said."The part of the narrator is as ___as the part of the princess." Over the next few weeks, with her encouragement, I learnt to take __ in the roie and worked hard to read over my lines. A few minutes____the play, I felt very nervous and then my teacher came over to me. "Yow mother asked me to give this to you,"she said,__ me a dandelion, one of the little flowers in my garden. As soon as I saw it, I __ and became confident. After the play, I took home the flower and pressed it __ two sheets of paper in a dictionary.1.A. slowly B. quickly C. easily D. quietly2.A. went away from B. came into C. went through D. ran to3.A. mind B. role C. way D. job4.A. So B. And C. Or D. But5.A. why B. if C. what D. when6.A. even B. still C. yet D. also7.A. answered B. nodded C. agreed D. shook8.A. anybody B. somebody C. nobody D. everybody9.A. cry B. crying C. laugh D. laughing10.A. necessary B. beautiful C. important D. good11.A. part B. interest C. pride D. chance12.A. before B. during C. after D. while13.A. handed B. handing C. hand D. to hand14.A. came down B. calmed down C. put down D. fell down15.A. around B. among C. behind D. between