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同类题1

下面文章中有五处需要添加小标题, 请从以下选项(A、B、C、D、E和F)中选出符合各段意思的小标题, 选项中有一项是多余选项。

A.Try to be a small animal doctor

B.Help to clean our city

C.Try to give the disabled a hand

D.Make  more money

E.Visit the old people's home

F.Raise money for poor students

     There are usually some people around us who need help. So it's great to be volunteers. But what can we do? Here are some great ideas.

____

    Not every child can go to school in our country. That's because most of them are too poor to pay for their education. But if we try to raise enough money for these students, they'll be able to finish their schools and have better futures.

____

      The city is our home. However, we pollute it every day. It's time to make it cleaner and greener. We should try to pick up rubbish whenever we see it. We can even go to clean up the city streets, the city parks or the rivers near our city when we are free.

____

      They usually have many problems with their everyday life. An easy thing for a common person may be very difficult for them. Reach out your hands to help to carry their bags, take them to cross the roads. Only a little help can make them feel warm

____

      Many of them have no sons or daughters, so they need someone to spend time with. On weekends or some special days, go to see them. It's a good idea to sing or dance for them. Or just tell them small stories to make them feel less lonely.

____

      They are our friends, but some of them are in danger. We should try to protect and save them. If you are lucky to be their doctor, you'll learn more about how to care for them. And when you see them get better, you'll feel happy and proud.

同类题4

在小英家的仓库里,堆放着一袋袋化肥一一碳酸氢铵( NH4HCO3).过了一个夏天,小英发现这种化肥所持有的刺激性气味变得更浓烈了,有些化肥袋里碳酸氢铵变少了,检查发现变少的化肥包装袋没有密封,化肥也没有撒落在地上,更没有人进过仓库开袋使用。

为了探究这些化肥减少的原因,小英在实验室取了一些碳酸氢铵粉末,放在蒸发皿中加热,过一会儿观察到粉末完全消失,同时也闻到了这种刺激性气味.粉末为什么会消失呢?

⑴【提出问题】碳酸氢铵粉末消失的原因是什么?

⑵【猜想】①碳酸氢铵粉末在不加热或加热条件下由固态变成它的气态。②碳酸氢铵在不加热或加热条件下发生分解反应,可能产生的物质有氨气和一些氧化物。

⑶【查阅资料】①碳酸氢铵属于氨肥,不具有升华的性质,说明上述猜想____ (填序号)不成立;②氨气(化学式NH3)具有特殊的刺激性气味,极易溶于水,其水溶液是碱性,但干燥的氨气不能使干燥的红色石蕊试剂变蓝;③NO2为红棕色气体。NO为无色气体,在空气中易发生反应:2NO+O2=2NO2

⑷【实验操作,现象与结论】

实验操作

实验现象

实验结论

①取适量碳酸氢铵于试管中加热,如图一所示,将干燥的红色石蕊试纸接近导管口

产生强烈的刺激性气味,试管壁上有无色液滴且试纸变蓝,但未见红棕色气体

分解产物中有____,没有____

②按如图二所示装置继续实验,直到反应完全

澄清石灰水变浑浊

分解产物中有____

⑸【应用】①利用氨气的化学性质,请写出实验室检验氨气的方法(写出实验操作、现象、结论):____

②如果你家里有碳酸氢铵化肥,你应该如何保存? ____