Can people change their skin color without suffering like pop king Michael Jackson? Perhaps yes.Scientists have found the gene that determines skin color.

　 The gene comes in two versions, one of which is found in 99 per cent of Europeans.The other is found in 93 t0 100 per cent of Africans, researchers at Pennsylvania State University report in the latest issue of Science.

Scientists have changed the color of a dark - striped zebrafish(斑马鱼) to uniform gold by inserting a version of the pigment(色素) gene into a young fish.As with humans, zebrafish skin color is deter-mined by pigment cells，which contain melanin(黑色素).The number, size and darkness of melanin perpigment cell determine skin color.

It appears that, like the golden zebrafish, light - skinned Europeans also have a mutation (变异) in the gene for melanin production.This results in less pigrnented skin.

　 However, Keith Cheng, leader of the research team, points out that the mutation is different in hu-man ancl zebrafish genes.

　 Humans acquired dark skin in Africa about l.5 million years ago to protect bodies from ultra - violetrays of the sun. which can cause skin cancer.

But when modem humans leave Africa to live in northem latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng.

Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin color, said Cheng.

The new discovery could lead to medical treatments for skin cancer.lt also could lead to research in-to ways to change skin color without damaging it like chemical treatment did on Michael Jackson.

56.Scientists have done an experiment on a dark -striped zebrafish in order to

A.fincl the different genes o humans'

B.prove the humans' skin color is determined by the pigment gene

C.find out the reason why the Africans' skin color is dark

D.fincl out the ways of changing people's skin color

57.lt can be inferred from the passage that　　　 .

A.nowadays people who want to change their skin color have to suffer 8 lot from the damage caused by the chemical treatment

B.Europeans and Africans have the same gene

C.the new discovery could help to find medical treatments for skin cancer

D.there are two kinds of genes

58.The passage mainly tells us that　　　 .

A.scientists have found out that people's skin color is determined by the gene

B.the new discovery could lead to research into ways to change skin color safely

C. pop king Michael Jackson often changed his skin color as he liked

D.people can not change their skin color without any pain

59.The reason why Europeans are light - skinned is probably that　　　 .

A.they are bom light - skinned people

B.light - skinned Europeans have mutation in the gene for melanin production

C. th　　　 ey have fewer activities outside

D.they pay much attention to protecting their skin

60.The writer's attitude towarcls the discovery is　　　 .

A.neutral　　　　　　　 B.negative　　　　　　　　　　 C.indifferent　　　　 D.positive

　 A group of graduates got together to visit their old university professor.They talked about the 36　 topic-happiness.But soon their conversation turned into complaints about 37 in work and life.

To offer his guests coffee, the professor went to the kitchen and 38 with a large pot of coffee and a variety of 39 plastic,glass, metal, porcelain (陶瓷), som plain-looking some very 40 .The professor told his students to help themselves to hot coffee.

　 When all the students had a cup of coffee in 41 . the professor said:"lf you have noticed, all the nice-looking 42 . cups were taken, leaving behind the plain and cheap ones.While it is　　 　43 for you to want only the best for Yourbelves, that is the 44 of your problems and stress.The professor continued," Believe that the cup itself adds no 45 to the coffee.ln most cases it is just more expensive and in some cases it even 46 what we drink.What all of you 47 wanted was coffee, not the cup, but you consciously went 48 the best cups.Now 49 this: life is coffee, the jobs, money,and 50 in society are the cups9 which are just tools to hold and 51 life, and the different typesof cups we have don't decide, nor 　52 the quality oflife.lf we concentrate only on the cups, we will 53 to enjoy the coffee in it.So don't let the cups 54 you...enjoy the coffee instead."

　 At these words, the graduates looked at each other in 55 embarrassment.

36.A.hot　　　　　　　　　　　 B.sensitive　　　　　　　　　 C.famous　　　　　　　　　　　　　 D.easy

37.A.pay　　　　　　　　　　 B.joy　　　　　　　　　　　　　 C.experience　　　　　　　　 D.stress

38.A.cooked　　　　　　　　 B.took　　　　　　　　　　　　 C.returned　　　　　　　　　 D.met

39.A.cups　　　　　　　　　　 B.gifts　　　　　　　　　　　　 C.plates　　　　　　　　　　　 D.drinks

40.A.common　　　　　　　 B.special　　　　　　　　　　　 C.rare　　　　　　　　　　　　 D.delicate

41.A.order　　　　　　　　　 B.time　　　　　　　　　　　　 C.hancl　　　　　　　　　　　 D.place

42.A. pretty　　　　　　　　 B. different　　　　　　　　　 C. colorful 　　　　　　　　 D. expensive

43.A.necessary　　　　　　 B.normal　　　　　　　　　　 C.good　　　　　　　　　　　　 D.possible

44.A.situation　　　　　　　 B.answer　　　　　　　　　　 C.result　　　　　　　　　　　 D.source

45.A.quality　　　　　　　　 B.energy　　　　　　　 　　　 C.weight　　　　　　　　　　 D.color

46.A.makes　　　　　　　　 B.gives　　　　　　　　　　　　 C.hides　　　　　　　　　　　　 D.includes

47.A. finally　　　　　　　　 B. really　　　　　　　　　　　 C. especially　　　　　　　　 D. nearly

48.A.for　　　　　　　　　　　 B.with　　　　　　　　　　　　 C.off　　　　　　　　　　　　　 D.to

49.A.forget　　　　　　　　　 B.discuss　　　　　　　 　 C.consider　　　　　　　　　 D.try

50.A. position　　　　　　　 B. relation　　　　　　　　　　 C. workmates　　　　　　　 D. friends

51.A.create　　　　　　　　　 B.support　　　　　　　　　　　　　 C.contain　　　　　　　　　　 D.own

52.A. damage　　　　　　　 B. determine　　　　　　　　 C. change　　　　　　　　　　　　　 D.increase

53.A.come　　　　　　　　　 B. stop　　　　　　　　　　　　 C.have　　　　　　　　　　　　 D.fail

54.A.drive　　　　　　　　　 B.hold　　　　　　　　　　　　 C.take　　　　　　　　　　　　 D.control

55.A. quiet　　　　　　　　　 B.speechless　　　　　　　　 C.amazing　　　　　　　　　 D.reasonable

—What do you think of that tea set as a gift for Mary's birthday?

—         .

A.My pleasure                                    B.I think it's a Chinese style

C.Not bad                                          D.Let me think it over

         that they may eventually reduce the amount of labor needed on construction sites by 90 per-cent.

   A.Such construction robots are clever    B.So clever the construction robots are

   C.So clever are the construction robots   D.Such clever construction robots are

I get the two of them mixed up        ; they are so similar.

A.at one time         B.at no time           C.in no time                  D. all the time

It  is said that people are        likely to tell lies over the phone as they are in emails.

A. as  twice          B. twice  as          C.twice  more             D. twice  than

Our bad living habits will destroy the earth.Only by changing        we live can we save the

earth．

A.that                    B.what                  C.how                          D.where

His suggestion made me angry, but        .

A.making others happy                              B.to make others happy

C.with others happy                                  D.others happy

With her eyes        the work attentively, she didn't know what was happening outside.

A . fixed  on                B.focused              C.fixing on                   D.focusing

—What happened to the young trees we planted?

—The trees        well, but I didn't water them.

A.might grow                                           B.needn't have grown

C.would grow                                          D.would have grown