日本成人片在线_久久免费精品视频_国产午夜精品久久久久久免费视_校花撩起jk露出白色内裤国产精品_av影片免费在线观看_国产小视频在线看_最新av免费在线观看_99久久99久久精品国产片_欧美成人猛片aaaaaaa_蜜桃免费网站一区二区三区

Thanks ________ the photo of your family.

[　　]

Best wishes ________ you.

[　　]

A．to	B．for
C．with	D．on

A．Happy Spring Festival!

B．Where are they from?

C．How are you?

D．How is the weather in Canberra?

E．I'd like to.

Li Ming and his mother are talking on the phone.

M: Hello, mom! This is Li Ming.

W: Hello, Li Ming! 1　　

M: I'm fine, thanks, mom. What about you and daddy?

W: Fine, too. It's winter here in Beijing and it's a little cold. 2　　

M: It's summer here now. It's hot.

W: Oh, I see. Are you getting on well（進展順利）with your English learning?

M: Yes. I have many good friends here. They help me a lot.

W: 3　　

M: Most（大多數）of them are from Australia. Some are from Canada, and some are from the U.K. and the U.S.

W: You can help each other（互相）.

M: Yes. I help them with their Chinese and they help me with my English.

W: Good. The Spring Festival is coming. Are you coming back to Beijing for it?

M: 4　　 But I'm afraid not（恐怕不能）. The Spring Festival isn't a holiday in Australia.

W: Oh, I see. Then take good care of yourself（好好照料自己）.

M: Thanks, mom. 5　　

W: The same to you. Good-bye!

M: Bye, mom.

On June 26, 2000, two scientists, called Francis Collins and Craig Venter, told the world that they could read the whole “map” of the human body: DNA. DNA is something that everybody has, and it tells the body what to do. DNA is the reason that we look like our mother and father, because we get some of their DNA to make our own.

People have been trying to understand the human body for a long time. In 1860, Gregor Mendel discovered a special reason why we look the same as other people in our family. It is because of small things named “genes” in our body. In 1953, James Watson and Francis Crick made another discovery and found out that those small parts are real messages written in the DNA with a special language.

In 1961, Marshall Nirenberg and Johann Matthaci found a message in DNA showing how DNA tells the cell（細胞）to build its parts. Scientists have now found all the words in the DNA map, but we still do not understand what they all do. By understanding what just one “word”   means, we can help save more people from several illnesses.

Most people hope that this will help make better medicine and help sick people. Other people worry that when people begin to know more words and find out lots of other information, we might use it in a wrong way, just to make people more attractive, or stop sick people from getting jobs. Man would have to meet a lot of trouble if DNA technic wasn’t limited（限制）in use.

(  ) 51. When did we first know why we look like other people m our family?

A. In 1860．      B. In 1953．       C. In 1961．      D. In 2000．

(  ) 52. What does the underlined word “ genes” mean?

A. The “map” of DNA.                B. A special language.

C. Small parts of DNA.                D. DNA.  ,,

(  )53. What did the two scientists first discover in 1961 ?

A. The “map” of DNA.                B. A new illness.        

C. The language of DNA.              D. A message of DNA.

(  ) 54. What can we do if we understand some “ words” of the language inside the body

A. Make people get new jobs.           B. Make medicine for illnesses.

C. Make maps of human.               D. Make people less attractive.

(  ) 55. What do people think about this work’?

A. It can cause good or bad results.               B. It can cause only good results.

C. It can cause good results but won’t work.        D. It can cause only bad results.

Who is responsible ________ this work?

[　　]

A．to	B．for
C．with	D．on