问题 单项选择题 B型题

点彩红细胞胞质中残存()

A.正常RNA

B.变性RNA

C.正常DNA

D.变性DNA

E.正常tRNA

答案

参考答案:B

解析:

1.网织红细胞(Ret)是晚幼红细胞脱核后到完全成熟红细胞间的过渡细胞,属于尚未完全成熟的红细胞,其胞质中残存嗜碱性物质核糖核酸(RNA),经活体染色后,形成核酸与碱性染料复合物,呈深染的颗粒状或网状结构。2.点彩红细胞是由于重金属损伤细胞膜,其胞质内核糖体发生变性聚集。

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When I first got an e-mail account ten years ago, I received communications only from family, friends, and colleagues. Now it seems that every time I check my e-mail,I have an endless series of advertisements and other correspondence that do not interest me at all. If we want e-mail to continue to be useful, we need specific laws that make spamming(发送垃圾邮件)a crime.

If lawmakers do not do something soon to prohibit spam, the problem will certainly get much worse. Computer programs allow spammers to send hundreds of millions of e-mails almost instantly. As more and more advertisers turn to spam to sell their products,individual e-mail boxes are often flooded with spam e-mails. Would people continue to use e-mail if they had to deal with an annoying amount of spam each time?

This problem is troubling individuals and companies as well. Many spam e-mails contain computer viruses that can shut down the entire network of a company. Companies rely on e-mail for their employees to communicate with each other. Spam frequently causes failures in their local communications networks, and their employees are thus unable to communicate effectively. Such a situation results in a loss of productivity and requires companies to repeatedly repair their networks. These computer problems raise production costs of companies, which are, in the end, passed on to the consumer.

For these reasons, I believe that lawmakers need to legislate(立法)against spare. Spammers should be fined, and perhaps sent to prison if they continue to disturb people. E-mail is a tool which helps people all over the world to communicate conveniently, but spam is destroying this convenience.

小题1:What does the underlined word “correspondence” in the Paragraph l probably mean?

A.messages

B.ideas

C.connections

D.programs小题2:According to the text, what is the major cause of the flooding spam?

A.Companies rely on e-mail for communications.

B.More people in the world communicate by e-mail.

C.Many computer viruses contain spam e-mail.

D.More advertisers begin to promote sales through spam.小题3:According to Paragraph 3, who is the final victim of spam?

A.The business.

B.The advertiser.

C.The employee.

D.The consumer.小题4:What is the purpose of the text?

A.To inform.

B.To educate.

C.To persuade.

D.To instruct.