以下()物品若经常使用,易引起中毒? A.带“釉上彩”的瓷器 B.锡壶 C.用废旧铝

题型:多项选择题

问题:

以下()物品若经常使用,易引起中毒?

A.带“釉上彩”的瓷器

B.锡壶

C.用废旧铝制品改制的餐具

D.竹筷

考点:食品安全知识竞赛食品安全知识竞赛题库
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学校买来6个书架,每个书架有5层,每层可以放45本书,这些书架一共可以放多少本书?

题型:多项选择题

下图表示利用胚胎干细胞(ES细胞)所作的一系列研究,请据图分析回答:

(1)过程Ⅰ将胚胎干细胞置于γ射线灭活的鼠胎儿成纤维细胞的饲养层上,并加入动物血清、抗生素等物质,维持细胞不分化的状态。在此过程中,饲养层提供干细胞增殖所需的___________,加入抗生素是为了____________________,这对于研究细胞分化和细胞凋亡的机理具有重要意义。

(2)过程Ⅱ将带有遗传标记的ES细胞注入早期胚胎的囊胚腔,通过组织化学染色,用于研究动物体器官形成的时间、发育过程以及影响的因素,这项研究利用了胚胎干细胞具有______________的特点。在哺乳动物早期发育过程中,囊胚的后一个阶段是_________。

(3)过程Ⅲ中目的基因导入胚胎干细胞最常用的方法是________,将获目的基因转入胚胎干细胞前需构建基因表达载体,其目的是___________________。

(4)过程Ⅳ得到的小鼠畸胎瘤中里面全是软骨、神经管、横纹肌和骨骼等人类组织和器官。实验时,必须用X射线照射去除胸腺的小鼠,获得免疫缺陷小鼠,其目的是_________________________,该过程研究的意义在于解决___________问题。

题型:多项选择题

大肠癌的好发部位依次为()

A.直肠、乙状结肠、升结肠、横结肠、盲肠、降结肠

B.直肠、乙状结肠、降结肠、横结肠、升结肠、盲肠

C.直肠、乙状结肠、盲肠、升结肠、降结肠

D.升结肠、横结肠、盲肠、乙状结肠、直肠

E.盲肠、升结肠、横结肠、乙状结肠、直肠

题型:多项选择题

豪华门扇的中冒头与门梃结合一般视冒头的宽度而定,梃与中冒头的截面尺寸相同,则为单榫结合;中冒头的截面宽度大于门梃截面宽度,则采用双榫结合。

题型:多项选择题

Did you ever look up at the moon and think you saw a man’s face there? When the moon is round and full, the shadows(影子) of the moon mountains and the lines of the moon valleys sometimes seem to show a giant nose and mouth and eyes. At least, some people think so.

  If there were a man on the moon—instead of mountains and valleys that just look like the face of a man—what would he be like?

  He would not be like anyone you know. He would not be like anyone anybody knows.

  If the man on the moon were bothered by too much heat or cold the way Earth people are, he could not stay on the moon.

  The moon becomes very, very hot. It becomes as hot as boiling water. And the moon becomes very, very cold. It becomes colder than ice.

  Whatever part of the moon the sun shines on is hot and bright. The rest of the moon is cold and dark.

  If the man on the moon had to breathe to stay alive, he couldn’t live on the moon because there’s no air there. He’d have to carry an oxygen tank, as astronauts do. There’s no food on the moon, either. Nothing grows—not even weeds(grass).

  If the man on the moon liked to climb mountains, he would be very happy. There are many high places there, such as the raised land around the holes, or craters(火山口), of the moon. Some of these rims are as tall as Earth’s highest mountains.

  But if the man on the moon liked to swim, he would be unhappy. There is no water on the moon—just dust and rock.

  When you think of what it’s like on the moon, you may wonder why it interests our scientists. One reason is that the moon is Earth’s nearest neighbor—it is the easiest place in space to get to.

  Going back and forth between the moon and Earth, astronauts will get a lot of practice in space travel. Things learned on moon trips will be of great help to astronauts who later take long, long trips to some of the planets.

  Scientists are also interested in the moon because it has no air. The air that surrounds Earth cuts down the view of the scientists who look at the stars through telescopes. A telescope on the moon would give them a clearer, closer view of the stars.(words: 411)

小题1:What is the reason why our scientists are interested in the moon.?

A.The moon is beautiful.

B.The moon is different from the earth.

C.The moon is Earth’s nearest neighbor—it is the easiest place in space to get to.

D.The moon is the easiest place in space to get to and it has no air, unlike Earth.小题2:The underlined word “rim” in the Paragraph 8 means _________ .

A.ball

B.hill

C.round edge

D.height小题3:What is the main thought of the passage?

A.We can learn much from research on the Moon.

B.There may be human beings on the moon.

C.If there were a man on the Moon, there would be many similarities between the man on the Moon and on the Earth.

D.A telescope on the Moon would help scientists have a clearer, closer sight of the stars.

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