问题 单项选择题

匡字形网页结构是同字形网页结构按()旋转后得到的。

A.顺时针90度

B.顺时针180度

C.逆时针90度

D.逆时针180度

答案

参考答案:C

阅读理解

Computer people talk a lot about the need for other people to become “computer-literate.” But not all experts (专家) agree that this is a good idea.

One pioneer, in particular, who disagrees is David Tebbutt, the founder of Computertown UK. Although many people see this as a successful attempt to bring people closer to the computer. David does not see it that way. He says that Computertown UK was formed for just the opposite reason, to bring computers to people and make them “people-literate.” David Tebbutt thinks Computertowns are most successful when tied to a computer club but he insists there is an important difference between the two. The clubs are for people who have some computer knowledge already. This frightens away non-experts, who are happier going to Computertowns where there are computers for them to experiment on, with experts to encourage them and answer any questions they have. They are not told what to do, they find out.The computer experts have to learn not to tell people about computers, but have to be able to answer all questions people ask. People don’t have to learn computer terms(术语), but the experts have to explain in plain language. The computers are becoming “people-literate.”

小题1:Which of the following is David Tebbutt’s ides on the relationship between people and computers?

A.Computer learning should be made easier.

B.There should be more computer clubs for experts.

C.People should work harder to master computer use.

D.Computers should be made cheaper so that people can afford them.小题2:We can infer from the text that “computer-lilerate” means_______.

A.being able to afford a computer

B.being able to write computer programs

C.working with the computer and finding out its value

D.understanding the computer and knowing how to use it小题3:The underlined word “it” in the second paragraph refers to the idea that Computertowns ___.

A.help to set up more computer clubs

B.bring people to learn to use computers

C.bring more experts to work together

D.help to sell computers to the public小题4:David Tebbutt started Computertown UK with the purpose of______.

A.making better use of computer expert

B.improving computer programs

C.increasing omputersales

D.popularising computers

单项选择题

一个细菌经过20分钟左右就可以一分为二,一根葡萄枝切成十段就可能变成十株葡萄,一株草莓依靠它沿地“爬走”的匍匐茎,一年内就能长出数百株草莓苗……凡此种种,都是生物靠自身的一分为二或一小部分的扩大来繁衍后代,这就是无性繁殖.无性繁殖的英文名称叫Cl0ne,译音为“克隆".现在,“克隆”的含义已不仅指无性繁殖,也包括“无性繁殖系”.凡是来自一个祖先的无性繁殖的一群个体叫“无性繁殖系”,简称无性系.自然界的许多动物,在正常情况下都是依靠父方产生的雄性细胞(精子)与母方产生的雌性细胞(卵子)融合(受精)成受精卵(合子),再由受精卵经过一系列细胞分裂长成胚胎,最终形成新的个体,这种依靠父母双方提供的性细胞,并经两性细胞融合产生后代的繁殖方法叫有性繁殖.但是,如果我们用外科手术将一个胚胎分割成两块、四块、八块……最后通过特殊的方法使一个胚胎长成两个、四个、八个……生物体,这些生物体就是克隆个体,而这一群个体就叫做无性繁殖系.克隆羊“多利”就是这样被“创造”出来的.英国爱丁堡罗斯林研究所的威尔莫特等人先给“苏格兰黑面羊”注射促性腺素,促使它排卵后,用极细的吸管从卵细胞中取出核.与此同时,从怀孕三个月的“芬多席特”六龄母羊的乳腺细胞中取出核,将它注入“苏格兰黑面羊"的卵细胞中,手术完成后,用相同频率的电脉冲刺激换核卵,让“苏格兰黑面羊”卵细胞质与“芬多席特”母羊乳腺细胞的核相互协调,使这个“组装”细胞在试管里经历受精卵那样的分裂、发育而形成胚胎的过程.然后,将胚胎巧妙地植入另一只母羊的子宫里.经过一段时间后,这只“护理”体外形成胚胎的母羊产下了小绵羊“多利”.“多利”不是由母羊的卵细胞和公羊的精细胞受精的产物,而是“换核卵”一步步发展的结果.克隆羊的诞生在世界各国引起了震惊,原因在于卵细胞中换进去的是体细胞的核,而不是胚胎细胞核.这个结果证明:动物体中执行特殊功能、具有特定形态的所谓高度分化的细胞与受精卵一样具有发育成完整个体的潜在能力也就是说,动物细胞与植物细胞一样,也具有全能性.

下列对第三自然段有关内容理解正确的一项是.

A.“多利”是科学家利用两只羊的不同细胞核而“组装”成的克隆羊

B.“多利”仍然是用母羊“护理”方法而生下的小绵羊,因而还不算真正意义

C.克隆羊胚胎形成的过程与受精卵形成胚胎的过程是相同的

D.“多利”是科学家利用试管受孕技术创造出来的小绵羊,因此被称为克隆羊上的克隆