除去下列物质中的少量杂质(括号里为杂质),所选用试剂及操作方法均正确的是( )

题型:选择题

问题:

除去下列物质中的少量杂质(括号里为杂质),所选用试剂及操作方法均正确的是(  )

选项物质(括号内物质为杂质)选用试剂操作方法
ACO2(CO)过量O2点燃
BCuO(Cu)适量稀盐酸过滤、洗涤、干燥
CNaCl溶液(CaCl2溶液)适量Na2CO3溶液过滤
DHNO3(H2SO4适量BaCl2溶液过滤

考点:水(蒸气)的检验粗盐的提纯空气的检验物质的相互转化和制备
题型:选择题

My mother used to ask me what is the most important part of the body. Through the years I would guess at what I thought was the correct answer.

When I was younger, I thought sound was very important to us as humans, so I said, “My ears, Mommy.”

She said, “No. Many people are deaf. But you keep thinking about it and I will ask you again soon.”

Several years passed before she asked me again. Since making my first attempt, I had thought about the correct answer. So this time I told her, “Mommy, sight is very important to everybody, so it must be our eyes.”

She looked at me and told me, “You are learning first, but the answer is not correct because there are many people who are blind.”

Then last year, my grandpa died. Everybody was crying. Mom looked at me when it was our turn to say our final good-bye to Grandpa. She asked me, “Do you know the most important body part yet, my dear?”

I was shocked when she asked me this now. I always thought this was a game between her and me. She said, “This question is very important. It shows that you have really lived your life.” I saw her eyes well up with tears. She said, “My dear, the most important body part is your shoulder.”

I asked, “Is it because it holds up your head?”

She replied, “No, it is because it can hold the head of a friend or loved one when they cry. Everybody needs a shoulder to cry on sometimes in life, my dear. I only hope that you have enough love and friends that you will have a shoulder to cry on when you need it.”

From then on, I knew the most important body part is not a selfish one. It is sympathetic(有同情心的) to the pain of others.

小题1:When did the writer understand her mother’s question?

                                                                              

小题2:Why did the girl’s mom ask her that question?

                                                                              

小题3:Is talking about that question a game between the girl and her mother?

                                                                              

小题4:Did the writer’s mother cry when her grandpa died?

                                                                                

小题5:What is the most important body part?

                                                                                  

题型:选择题
49
79
的分子、分母里,都减去一个相同的整数,就成了
2
7
.这个相同的整数是______.
题型:选择题

根据规定,我国企业事业单位都应该采用权责发生制。(  )

题型:选择题

矿渣硅酸盐水泥的密度大小范围为:()

A、3.0~3.2

B、2.8~3.1

C、2.6~2.8

题型:选择题

未衰老的红细胞过早破坏与下列机制有关,但除了()

A.脾功能亢进

B.红细胞内血红蛋白聚集或沉淀

C.红细胞内酶异常

D.红细胞内血红蛋白减少

E.红细胞膜附着有不完全抗体或补体

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