题干

如图,把△COD扩大后得到△AOB,若点C,D,B的坐标分别为C(1,2),D(2,0),B(5,0).则点A的坐标为(  )

A:(2,5)

B:(2.5,5)

C:(2,5)

D:(3,6)

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答案(点此获取答案解析)

B

同类题1

阅读短文,完成各题

雾霾

    ①雾霾是雾和霾的统称。

    ②雾是大量悬浮在近地面空气中的微小水滴或冰晶导致水平能见度降低到1000米以内的天气现象。雾看起来呈乳白色或青白色。

    ③霾是空气中的灰尘、硫酸、硝酸、有机碳氢化合物等粒子使大气浑浊,并导致水平能见度小于10000米的现象。霾看起来呈黄色或橙灰色。

    ④雾和霾常常相伴出现。区别雾和霾,空气相对湿度是重要依据。一般相对湿度小于80%时的空气能见度恶化主要是霾造成的,人们习惯上称此时的天气为霾天;相对湿度大于90%时的空气能见度恶化主要是雾造成的,通常被称为雾天;相对湿度介于80%~90%之间时的空气能见度恶化是霾和雾的混合物共同造成的,一般被统称为雾霾天。

    ⑤在雾霾天气中,PM2.5是“罪魁祸首”。其主要来源有多个:一是道路扬尘和建筑施工扬尘;二是汽车尾气;三是工厂制造出的废气污染;四是冬季取暖时燃烧煤炭低空排放的污染物;五是生物质(如秸秆、木柴)的燃烧以及垃圾焚烧产生的烟尘。

    ⑥这些污染颗粒和细菌、病毒等一起附着在水滴上,危害着人的健康。1952年12月,英国伦敦大雾一周不散,烟尘废气在低空聚积,其间有4700人因呼吸道疾病死于非命,雾散后,还有8000多人因雾死亡。“雾都劫难”震惊世界,人们将伦敦雾灾列为20世纪世界十大自然灾害之一。

    ⑦雾霾天应减少开窗,减少外出。但最根本的还是要从源头上采取“减排消尘”的措施。此法既能减少由温室气体引发的空中水汽,又能减少空气中的凝结核,从而达到控制雾霾频发现象的目的。这方面伦敦做出了榜样:1956年英国颁布了“清洁空气法案”,在“减排消尘”上大做文章,如今已见成效,原来每年有几十个雾霾天,现已降至5天,世界著名的“雾都”已名不副实。

同类题5

阅读下面短文,从短文后各题所给的四个选项(A, B, C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。

     “Daily Star, sir” called Jason, carrying some newspapers under his arm. The little boy had been running up and down the street, but there were still twenty 1 left. His voice was almost gone and his heart was 2. The shops would soon close, and all the people would go home. He would have to go home too, carrying the papers 3 money. He had hoped to sell more papers tonight to make more money to buy a4for his mother and some seeds for his bird. That was why he had bought the papers with all his money. He 5 as he thought of his failure to sell all his papers.

     “You don't know the 6of selling papers. You must shout, “Hot news! Bomb bursting!” another newsboy Chad told Jason. “7 it's not in the paper at all,” replied Jason. “Just run away quickly 8they have time to see, and you'll 9out and get your money,” Chad said.

    It was a new 10to Jason. He thought of his bird with no 11 and the cake he wanted to buy for his mother, but was 12 that he would not tell a lie. Though he was 13 a poor newsboy, he had been 14 some good things.

The next afternoon Jason went to the office for his papers 15 Several boys were crowding around Chad, who declared with a 16 smile that he sold six dozen the day before. He added that Jason 17 money because he would not tell a lie. The boy 18 at Jason. “You wouldn't tell a lie yesterday, my boy?” A gentleman at the office came up and patted Jason's shoulder 19.”You're just the boy I am looking for.” A week later, Jason started his new20. He lost sale of twenty papers because he would not tell a lie, but got a well-paid job because he told the truth.