现有亚硝酸钠、熟石灰、氢氧化铝、硫酸铜四种物质．其中______可_爱下问搜题

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问题填空题

现有亚硝酸钠、熟石灰、氢氧化铝、硫酸铜四种物质．其中______可用作医药上中和过多的胃酸；______可用来配制农药波尔多液；工业用盐______误作食盐，食用后会使人中毒．

答案

氢氧化铝可以和盐酸反应，可用作医药上中和过多的胃酸；熟石灰和硫酸铜反应生成氢氧化铜沉淀和硫酸钙，可用来配制农药波尔多液；工业用盐中含有亚硝酸钠，亚硝酸钠有毒，食用后会使人中毒．

故答案为：氢氧化铝[Al（OH）₃]；熟石灰和硫酸铜[Ca（OH）₂和CuSO₄]；亚硝酸钠[NaNO₂]．

不定项选择

不定项选择

摆长为l的单摆做简谐运动，若从某时刻开始计时（即取作t=0），当振动至

时，摆球恰具有负向最大速度，则单摆的振动图象是图中的（）

A．

完形填空

I was very fond of hunting when I was a young man. In the autumn of 1915, I was __16__ in the northwest of India. One evening, after hunting in the forest all __17__， I was returning alone to the place where I had __18__ up my tent. I was tired __19__ hungry. It was getting __20__ and darker, and I was walking slowly __21__ a narrow path. On my right was a wide river; on my left, a __22__， dark forest. All of a __23__ I saw two green eyes looking at me from among the trees. I knew it __24__ be a man-eating tiger. The tiger was getting ready to __25__ on me.
My heart __26__. What could I do? Should I jump __27__ the river and hope to save my life __28__ swimming? I looked to the __29__. In the river there was a __30__ crocodile waiting to welcome me with its mouth __31__ open. I was so __32__ that I shut my eyes. And I thought it would be the end of my __33__. I heard branches moving __34__ the tiger roared (咆哮) and jumped. __35__ then I opened my eyes. What do you think had happened? The tiger had jumped right over me and now in the jaws (嘴) of the crocodile.