问题 选择题

每一种生物细胞核内的染色体数目是一定的.人的体细胞中染色体的数目是(  )

A.46条

B.36条

C.23条

D.64条

答案

体细胞中染色体是成对存在;不同的生物个体,染色体的形态、数目完全不同; 同种生物个体,染色体在形态、数目保持一定,即每一种生物的体细胞内,染色体的形态和数目都是一定的,如正常人的体细胞中含有23对染色体,即46条.

故选:A.

阅读理解

Can you imagine a world without the Internet? It’s surprising to think about it.

Now, China has more than 162 million Internet users, according to the China Internet Network Information Centre. This is the second highest number of user in the world after the United States. Today, 66%of Chinese “netizens (网民)” are teenagers. “They spend about thirteen hours every week online,” said Qian Hulin, an Internet expert(专家). Doctor Song in Beijing Xuanwu Hospital said about 14% of Chinese netizens who are teens often lasted over ten hours to play online games.

The main reasons why teenagers surf the Web are to search for information, to communicate with others and to have fun. On the Internet, teenagers can find out almost anything. And surfing the Web can help students with their homework and widen their knowledge.

Li Dong, a teacher at No. 41 Middle School in Shijiazhuang, likes her students to use the Internet. “When we talk in class, students who surf the Net usually know more background information than the others,” she said.

In addition, people can use the Internet to write letters or stories and send e-mails. Many teens keep in touch with their friends online. It is cheaper than phoning somebody far away and also much quicker.

小题1:_______ has the most Internet users in the world according to the article.

A.China

B.America

C.Canada

D.Russia小题2:There are about _______ Chinese netizens to surf about 13 hours every week.

A.107 million old

B.22.7 million old

C.107 million young

D.22.7 million young小题3:Song said some teenagers continued _______ more than ten hours.

A.playing online games

B.searching for information

C.chatting with their friends

D.sending e-mails to others小题4:Li Dong in No. 41 Middle School likes her students to use the Internet because she

______.

A.thinks surfing the net can help students spend less time on homework

B.thinks her students can get more background information than the others

C.wants her students to talk to her about their hobbies and interests

D.wants to know what her students do and think about at home小题5:Which way is the cheapest and quickest to learn something about friends far away?

A.Giving them a call.

B.Going to see them.

C.Writing a letter to them.

D.Sending e-mails to them.

选择题