While watching television, __________.

                A．the doorbell rang                           B．the doorbell rings

            C．we heard the doorbell ring          D．we heard the doorbell rings

One day last September, as Britney Spears was about to board a flight to Los Angeles from London, a blue bottle fell out of her purse. She quickly put it back in, but not before the camera recorded the event. Neither Spears nor her spokesman was willing to comment on the contents of the bottle, but the next morning London’s Daily Express published a page of pictures under the headline “EXCLUSIVE: POP PRINCESS SPOTTED AT AIRPORT WITH POT OF SLIMMING TABLETS.” Spears was apparently carrying Zantrex-3, one of the most popular weight-loss pills now sold in the United States. The pill, which is sold at about fifty dollars for a month’s supply, contains a huge amount of caffeine, some green tea, and three common South American herbs that also act as stimulants (兴奋剂). It hit the U.S. market last March and has had a success that would be hard to overstate. Millions of bottles have been sold, and during the Christmas season it was displayed in the windows of the nation’s largest chain of vitamin shops, G.N.C. (It is so highly sought after that many of the stores keep it in locked counters.) Zantrex-3 is also sold at CVS, Rite Aid, Wal-Mart, and other chains, and over the telephone and on the Internet. If you type “Zantrex” into Google, more than a hundred thousand pieces of information about it will appear. At any moment, there are scores of people sell it on eBay.

Perhaps the most interesting thing about the success story of Zantrex-3, however, is that it is far from unique. There are hundreds of similar products on the market today, and they are bought by millions of Americans. And though Zantrex’s producer makes some exciting statements (“the most advanced weight control compound (化合物)period”), so do the people who sell Stacker 2 and Anorex along with those who sell Carb Eliminator and Fat Eliminator. Almost all of these compounds suggest that they can help people lose weight and regain lost energy, and often without diet, exercise, or any other effort.

51. Britney Spears is a / an______.

   A. dancer          B. singer           C. athlete         D. chemist

52. Which of the following is also a kind of weight-loss pill?

   A. CVS           B. Rite Aid          C. Wal-Mart       D. Anorex

53. The underlined part of the sentence in the first paragraph is most likely similar in meaning to ______.

   A. it is difficult to say how successful Zantrex-3 is

   B. you can’t overstate the success of Zantrex-3

   C. you can’t think too highly of the success of Zantrex-3

   D. Zantrex-3 is not very successful

54. From the second paragraph we know that ______ .

   A. Zantrex-3 is one of the successful weight-loss pills on the US market

   B. Zantrex-3 is the most successful weight-loss pills on the US market

C. Zantrex-3 is the only weight-loss pill on the US market

D. there are five kinds of weight-loss pills on the US market

55. The text mainly tells us ______.

   A. when Britney Spears was found taking weight-loss pills with her

   B. how Zantrex-3 became successful in the USA

   C. weight-loss pills are very popular in the USA

   D. Zantrex-3 is forbidden to be sold on the US market

. His grandfather was among the first to settle in ____is now a famous holiday center.

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

With an electronic typewriter ,we can get evenly typed characters regardless of the pressure ________we strike the keys.

A.     that  B. with which  C. that  D. by that 

When she came out, Mary looked a bit tired because she _____the house.

A. cleaned  B. was  C. had cleaned  D.had been cleaning

This kind of foods which are already prepared for cooking are_____ in supermarket.

A.     ready  B. probable  C. available  C. approachable

A healthy life is frequently thought to be___ with the open countryside and homegrown food.

A.     associated   B. bound   C. related  D. tied

Mom promised to buy me a nice gift for my bithday,_____beyond my imagination.

A.     which  B.that  C.something  D.the one

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

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

Scientists have changed the colour of a dark-striped zebrafish to uniform gold by inserting a version of the pigment(色素) gene into a young fish. As with humans, zebrafish skin colour is determined by pigment cells, which contain melanosomes(黑色素). The number, size and darkness of melanosomes per pigment cell determines skin colour.

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

However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebrafish genes.

Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun(太阳光紫外线), which can cause skin cancer.

But when modern humans leave Africa to live in northern 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 colour, said Cheng.

The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin colour without damaging it like chemical treatment did on Michael Jackson.

51. The passage mainly tells us that ________.

  A. people can not change their skin colour without any pain

  B. the new discovery could lead to search into ways to change skin colour safely

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

  D. scientists have found out that people’s skin colour is determined by the gene

52. It can be inferred from the passage that ________.

  A. nowadays people who want to change their skin colour have to suffer a 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

53. Scientists have done an experiment on a dark-striped zebra fish in order to ________.

  A. find the different genes of humans’

  B. prove the humans’ skin colour is determined by the pigment gene

  C. find out the reason why the Africans’ skin colour is dark

  D. find out the ways of changing peopl’s skin colour

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

  A. they are born light-skinned people

  B. light-skinned Europeans have mutation in the gen for melanosome production

  C. they have fewer activities outside

  D. they pay much attention to protecting their skin

55. The writer’s attitude towards the discovery is ________.

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

—Could I use your dictionary?

—I’m sorry it isn’t here. I’d get it for you_______ I could remember who last borrowed it.

A. expect that                  B. now that   

C. only if                      D. even though