问题 单项选择题

在细胞同期中,RNA的质和量在不断变化,因而早合成的DNA所接触的RNAs(细胞中 RNA小片段的总和)不同于晚合成的DNA,失活的X染色体复制迟,松散的染色质复制早,早复制的DNA会接触更多的RNAs,从而维持较高的活性。
符合上文原意的是( )。

A.早合成的DNA,失活的X染色体复制也早

B.晚合成的DNA,接触的RNAs多一点

C.晚合成的DNA,其活性要高

D.染色质复制早的话,DNA会接触到更多的RNAs

答案

参考答案:D

解析:A错误,早合成的DNA,失活的X染色体复制应该是晚;B错误,晚合成的DNA,接触的 RNAs要少一点;C错误,早合成的DNA在活性上要高于晚合成的DNA。

完形填空

阅读下面的短文并回答问题,然后将答案写到相应的位置上(请注意问题后的词数要求)。

[1]E-mail may be the most important, unique method for communicating and developing relationships since the telephone.First of all, ____________.Anyone who can use a word processor can also write an e-mail message without difficulty.Secondly, it saves time and money.It costs nothing more than your time.No paper expense, no postage and no envelope expense.People also find it familiar and safe because it is similar in many respects to writing letters but avoids the annoyances of addressing envelopes, licking stamps, and trips to the mailbox.

[2] Of all the methods for developing relationships on the Internet, e-mail is the most common and perhaps the most powerful.Although friendships and romances may indeed begin in chat rooms, instant messages, blogs, or other online tools improve greatly by becoming more effectively visual and auditory(听觉的), as in video teleconferencing, e-mail will not disappear.Many people will prefer it because it is a non-visual and non-auditory form of communication.After all, we don’t see people rushing out to buy video equipment to add it to their telephone.

[3] E-mail is not just an electronic mail sent via the Internet.It creates a psychological space in which pairs of people or groups of people communicate with each other.It creates a situation in which human relationships can be unfolded.

小题1:What is the main idea of the text? (no more than 12 words)

                                                                           

小题2:Complete the following statement with words from Paragraph 2.(no more than 4 words )After people begin their relationship in chat room, e-mail plays the role of being a way to        

                                                                           

小题3:Fill in the blank in Paragraph 1 with proper words.(no more than 6 words )

                                                                           

小题4:What situation can the E-mail create? (no more than 9 words )

                                                                           

小题5:What does the underlined word “ it ” (Paragraph 2) probably refer to ? (no more than 3 words )

                                                                           

单项选择题