人类需要洁净的空气，为消除煤炭燃烧产生的二氧化硫，人们向煤炭_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题填空题

人类需要洁净的空气，为消除煤炭燃烧产生的二氧化硫，人们向煤炭中加入石灰石做______，请你写出该过程的化学方程式______、______．汽车尾气是大气污染物之一，为减小有害气体排放，人们在汽车排气管上安装“催化转化器”，使一氧化碳和一氧化氮进行转化，其转化的化学方程式为______．

答案

向煤中加石灰石主要起固硫作用，原理如下：首先是石灰石在高温下分解，CaCO₃

高温

.

CaO+CO₂↑，生成氧化钙，氧化钙再吸收煤燃烧产生的二氧化硫，CaO+SO₂=CaSO₃，从而起到固硫的作用．

一氧化碳和一氧化氮在催化剂下发生反应，必须生成无污染的物质，一氧化碳转换二氧化碳，一氧化氮转换为氮气，方程式为2NO+2CO

催化剂

.

N₂+CO₂↑

故答案为：固硫剂；CaCO₃

高温

.

CaO+CO₂↑；CaO+SO₂=CaSO₃；2NO+2CO

催化剂

.

N₂+CO₂↑

选择题

喜食蔬菜而不食肝脏、鱼肝油等动物性食物的人不一定患夜盲症，原因是蔬菜中含有（）

A 、胡萝卜素 B 、维生素B C 、维生素C D 、维生素A

完形填空

In fact, everyone has an angel（天使）protecting himself forever.
If this   36  feels that your life is full of   37  and you always feel terribly sad. She would   38  someone else beside you. Maybe it’s a friend of you, or your lover,      39  a net-friend you have never met or a 40  you just met only once. These persons quietly __ 41  in your life, accompany (陪伴) you with a happy time and   42  he could leave silently. And thus your life is full of happy   43 . Even the future path is covered with storm or snow,   44  remembering those happy stories he 45 to you, you can still be brave.
For those   46  have left you without any   47 ,   48 they are angels returning to the heaven. For example, your lost friends, the strangers who ever gave you help, those separated but   49  love you, those artists who used to sing good songs to you, the good writer and etc.., they are all   50  angels.
Perhaps sometimes you   51  feel sad or lost because of their   52 , and would look for them everywhere to   53  where they’re going. But in the end, you’ll be certain that they stay in   54  place of this world with a peaceful and thankful life.   55 , all the feelings of loss and sadness will no longer exist since time has been the greatest therapist(理疗师).

C．together with

小题6:A enter B. appear C. arrive D. settle

D．thus（因此）

A．information

B．cold-blooded

C．kind-hearted

C．disappearance