题干

长期受电磁辐射可引起人头昏、头痛、失眠等症,科学家发现富含维生素的食物具有较好的防辐射损伤功能。下列食物中富含维生素的是(   )

A:油菜

B:牛奶

C:豆腐

D:米饭

上一题 下一题 0.0难度 选择题 更新时间:2018-10-22 06:37:49

答案(点此获取答案解析)

A

同类题1

阅读理解

    Glacier Bay is one of the most famous parks in America, located in the state of Alaska. This park in the southeastern part of the state covers more than 1 million hectares of Alaskan wilderness. It includes mountains, glaciers (冰川), bays, and even rainforests. Glacier Bay supports hundreds of kinds of animals, including many species of birds, fish, bears, whales and sea lions.

    As its name suggests, much of Glacier Bay National Park is covered by glaciers. A glacier is a large area of ice that moves slowly down a slope (斜坡) or valley, or over a wide area of land. Glaciers cover more than 5,000 square kilometers of the park.

    Glacial ice has shaped the land over the last seven million years. The glaciers found in the park today are what remains from an ice advance known as the Little Ice Age. That period began about 4,000 years ago.

    During the Little Ice Age, the cold weather caused the ice to grow and advance. That situation continued until about 1,700s, when the climate began to warm. The higher temperatures caused the ice to start melting. That melting led the huge glacier to separate into more than 1,000 different glaciers.

    The extremely tall and jagged (参差不齐的) mountains seen in Glacier Bay National Park were formed by the ice advancing and then melting over time. The melting of the ice also created water that filled in and created the many fjords (峡湾) within the park. Fjords are narrow parts of the ocean that sit between cliffs or mountains.

    The huge amount of water from the melted ice killed off many kinds of plants. Vegetation returned to the area over the next 200 years. The regrowth in plants also brought back many animals to the land. This return of life to Glacier Bay is why it is sometimes called “a land reborn” by people.

同类题5

阅读下面的文字,完成下列小题。

卡拉维拉斯驰名的跳蛙

【美】马克吐温

    这里从前有过一个叫吉姆·斯迈雷的。只要能找到一个人愿打赌,他就赔同,碰上什么就赌什么,十有八九总是他赢。

    他有一只小斗狗,光看外表你准以为它一钱不值,就配在那儿拴着,一副贼溜溜的样子,老想偷点什么。可是,一旦在它身上下了注,它转眼就变了一条狗;它的下巴颏往前伸着,就像火轮船的前甲板,下槽牙都露了出来,像煤火一样放光。斯迈雷老是靠这条狗赢钱,直到在一条没后腿的狗身上碰了钉子。

    那一次,两条狗斗了好一阵子,两边的钱都押完了,斯迈雷的那条狗上去照着咬惯了的地方下嘴的时候,当时就看出自个儿上当了,它让人骗惨了。它朝斯迈雷瞧了一眼,好像是说它伤透了心,这都是斯迈雷的错,怎么弄了一条没有后腿的狗来让它咬呢,斗狗时它本来靠的就是咬后腿嘛。

    有一天,他逮着一只跳蛙带回家去,说是要好好训一训。果不其然,他把跳蛙训出来了。只要他从后头点跳蛙一下,那跳蛙像翻煎饼一样在空中打个转,然后稳稳当当地脚朝下落地。我就瞧见过他把丹尼尔·韦伯斯特放在这儿的地板上——那跳蛙叫丹尼尔·韦伯斯特——大喊一声:“苍蝇,丹尼尔,苍蝇!”跳蛙就噌噌地照直跳起来,快得让你来不及眨眼,把那边柜台上的一只苍蝇吞下去了,然后像一摊泥“扑嗒”落在地上,拿后腿抓耳挠腮,没事人似的。

    斯迈雷拿一个小笼子盛着那跳蛙,时不时地带着它逛大街,设赌局。有一天,一个汉子——他是个外乡人——到屯子里来,正碰上斯迈雷提着跳蛙笼子,就问:“你那笼子里头装的是什么呀?”

    斯迈雷冷着个脸说:“它是一只跳蛙。”

    那汉子拿过笼子,转过来转过去,细细地瞅,说:“嗯——原来是个跳蛙,它有什么特别的呀?”

    “噢,”斯迈雷不紧不慢地说,“它就有一件看家的本事,要叫我说——它比这卡县地界里的哪一只跳蛙蹦得都高。”

    那汉子拿过笼子,又仔仔细细地看了好半天,才还给斯迈雷,慢慢吞吞地说,“是嘛,”他说,“我也没瞧出来这跳蛙比别的跳蛙能好到哪儿去。”

    斯迈雷说,“别管你怎么看,我心里有数,我赌四十块钱,敢说这跳蛙比卡县随便哪一只跳蛙都蹦得高。”

    那汉子琢磨了一会儿,有点儿作难:“呃,这儿我人生地不熟的,也没带着跳蛙;要是我有一只跳蛙,准跟你赌。”

    这时候斯迈雷说话了:“好办,好办,只要你替我把这笼子拿一小会儿,我就去给你逮一只来。”

    斯迈雷离开后,这汉子坐在那儿想来想去,想了好一会儿,然后从笼子里头把跳蛙拿出来,扒开它的嘴,自己掏出一把小勺来,给跳蛙灌了一肚子火枪的铁砂子,一直灌到齐了跳蛙的下巴颏,然后把跳蛙放到地上。斯迈雷呢,他上洼地的烂泥里头稀里哗啦趟了一气,到底逮住个跳蛙。他把跳蛙抓回来,交给那汉子说:“行了,你要是准备好了,就把它跟丹尼尔并排摆着,把他的前爪跟丹尼尔的放齐了,我喊个号。”然后他就喊:“一——二——三——蹦!”他和那汉子从后边点那两只跳蛙,那只新来的跳蛙蹦得特有劲,可是丹尼尔喘了一口粗气,光耸肩膀——就这样——像法国人似的。这哪管事儿啊;它动不了,跟生了根一样,连挪挪地方都办不到,就像抛了锚。斯迈雷说什么也想不通这到底是怎么一回事。

    那汉子拿起钱就走,临出门了,他还拿大拇指在肩膀上头指指丹尼尔,慢慢吞吞地说:“我也没瞧出来这跳蛙比别的跳蛙好到哪儿去嘛。”

    斯迈雷呢,他站在那儿抓耳挠腮,低着头把丹尼尔端详了好一会儿,最后他揪着丹尼尔脖子上的皮,把跳蛙掂起来,跳蛙头朝下,喷出满满两大把铁砂子来。这时候斯迈雷才明白过来,他气得发疯,放下跳蛙就去追那汉子,可再也追不上了。