题干

小明同学对所学部分化学知识归纳如下,其中完全正确的一组是(   )

①物质的分类

②资源的利用和保护

①合成橡胶、合金都属于合成材料

②氧化物中含有氧元素

③混合物中一定含有多种元素

①保护空气要减少有害气体和烟尘的排放

②爱护水资源要节约用水和防止水体污染

③保护金属资源只能通过防止金属腐蚀实现

③“低碳经济”的措施

④用“化学”眼光分析

①改造或淘汰高能耗、高污染产业

②研制和开发新能源替代传统能源

③减少使用一次性塑料方便袋

①洗涤剂去油污是因为起乳化作用

②湿衣服晾干是因为分子之间有间隔

③明矾净水是因为明矾溶于水生成胶状物

A:①

B:②

C:③

D:④

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答案(点此获取答案解析)

C

同类题1

阅读下面短文,掌握大意,然后从每题所给的A、B、C、D四个选项中选出最佳选项。
A Second Chance

    I grew up as a foster(收养的) child from the day I was born. I never really had a biological(有血亲关系的) mother. I never experienced the 1a mother gives her child. Five years ago, I came to my second foster home. It was a 2 family, but still something pained me deeply. I wasn't her birth child. So I don't allow myself to get close to 3 . I felt "out of place".   
    In one night, 4, things changed. I was doing homework while waiting for the family to return home. Feeling so bored, I spent the night alone finding things to keep me 5. As I was reading a book, I heard the closing of the back door and my foster mom 6me. I walked into the kitchen where she was holding a children's book. "I want you to read this book. It's really wonderful!" She said 7 . She handed me the book, I had a quick look at it: The Kissing Hand. I wanted to question her when she 8me. "Trust me. You'll love it."
    It was (a)9of a raccoon(浣熊)mom who places a kiss in the palm(手掌)of her child's hand. She wants to let him know if he is  10, he just needs to put his Kissing Hand to his face. That 11 he can always remember his mom loves him.
Later that night, I was sitting on the sofa when 12 mom did something really unexpected. She gently took my hand and put a warm loving 13 in the center of my palm. Then she quietly closed my hand, held it between hers and spoke words that I had 14to hear for so long. "Whenever you get afraid or sad, don't forget your mom loves you."
    As the tears began to form in my eyes, I began to understand. I truly do have a 15 . No, she wasn't biological, but she was mine just the same.