It takes a very unusual mind to undertake         of          obvious.

A. analysis；an             B. analyses；an   C. analysis；the  D. analyses；the

 Once        ，a word becomes a promise.

A. speak                B. spoken              C. speaking         D. to speak

It was        she took off her dark glasses       I realized she was a famous film star.

A. when；that              B. that；that     C. that；when       D. when；then

He still keeps in        with his college classmates.

A. relation                   B. tie                    C. link            D. touch

Japanese doctors have used thin sheets of tissue(肌肉组织)from people’s cheeks repair damaged corneas（角膜）. A team from Osaka University transplanted thin layers of cheek cells onto the eyes of four patients with a rare and painful eye condition，reports BBC online. Patients whose vision had been cloudy could see well afterwards，and the“new corneas”remained clear more than a year after the operation.

Doctors can also take cells from a healthy eye and grow them in a dish to produce a new cornea，or they can transplant corneas from donors（捐献者）. But these techniques may not work when both eyes are too badly damaged by accident or disease.

The team hope their work may help solve the problem and lead to other types of grow－your－own tissue transplants. The cornea is the clear layer of cells on the surface of the eye. It can be damaged by trauma（外伤）or by a range of diseases.

The team worked with four patients who had a painful condition that causes cloudy corneas and dry eyes. Often the eye can regenerate(再生) cornea cells but none of the four patients had this ability. The researchers took a 3 mm－wide square of tissue from inside the mouth（cheeks）and grew it into a thin layer in the lab. They used a special low temperature technique to separate a very thin sheet off each batch. They then laid that onto the patient’s eye. The cell layers stuck onto the eye and developed into tissue that looked and acted like a healthy cornea.

However，long－term follow－up and experience with a large series of patients is needed to assess the benefits and risks this method. Yet，“it does offer the potential（潜能）of treating severe eye diseases that are resistant to standard approaches，”said the head of the research，Kohji Nishida.

48. Now doctors can repair the damaged corneas with the following methods Except_______.

A.  by using mouth tissue       

B.  by taking cells from a healthy eye and growing them in a dish

C.  by transplant corneas from another person

D.  by using finger tissue

49.  If both eyes are too badly damaged，we can treat them _________.

A.  only by using mouth tissue       

B.  by taking cells from a healthy eye and growing them in a dish

C.  by transplant healthy corneas from donors

D.  by none of the mentioned method

50.  We can infer from the passage___________.

A.  the new technique can be widely used in the operations

B.  the new technique needs to be further tested

C.  the new technique has more benefits than risks

D.  any new technique has risks

51.  Which of the following is the best title？

A.  A new invention                                          

B.  A new technique

C.  Mouth tissue can restore your vision               

D.  Transplanting can restore your vision

Empty Deserts

In the 19th century Americans from the eastern states moved out west to settle in the rich new lands along the Pacific coast.  The most difficult part of their trip was crossing the “Great American Desert in the western part of the United States by horse and wagon.

The western desert can be very dangerous.  There is little water and there are few trees.  But the desert also has scenery of great beauty.  Tall towers of red and yellow stone rise sharply from the flat sandy valley floor.  The scene has been photographed many times and appears in movies and in TV.

In Arizona, man made dams(大坝) across the Colorado River have made two large lakes in the middle of the dry desert country.  At Lake Powell, the red stone arch（弓形结构） of Rainbow Bridge rises high above the blue lake.

There are few roads.  Many areas of Lake Powell’s shore can only be reached by boat or on foot.  But hikers in this empty desert land sometimes find very old native American pictures, painted on the rocks.

In Death Valley, California, the summer temperature rises to 130 degrees.  There is less than two inches of rain each year.  Death Valley is the lowest place in America―― 925 meters below sea level.  In the 1800s, many travelers died when they tried to cross this waterless valley in the terrible heat.

     Although the desert is dry and seems empty, there is plenty of life if you look closely.  Small insects, snakes and rats have learned how to live in the desert heat.  They live under ground and come out at night, when it is cool.  Plants such as cacti need very little water.   When it does rain in the desert (sometimes only once or twice a year), plants grow quickly, and flowers open in a single day.  For a short time, the desert is covered with brilliant colors.

36. In the 19th century, Americans moved from the east to the west because they ______.

A.  enjoy the trip                                              

B.  wanted to make their home there

C.  wanted to find new grassland there                

D.  had no water to drink

37. From the passage, we can conclude that ______.

A.  the western desert is a good place for people to live in

B.  there is little water but there are many trees in the desert

C.  the desert is dangerous but it is full of life

D.  till now, people know little about the desert

38. In the 1800s many travelers died in Death Valley because of ______.

A.  illness                                            B.  high temperature                 

C.  cold weather                                  D.  poisonous water

39. In the desert, animals will die ______.

A.  if they move about                                      

B.  if they cannot make holes underground

C.  if they come out at night                              

D.  if they drink much water

     What are the basic elements of good manners？Certainly a strong sense of justice is one. Courtesy （礼貌）is often  16   more than a highly developed sense of fair play. A friend of mine once told me of  17 along a one－lane (单行道)，unpaved(未铺好的)－mountain road.  18   was another car that produced clouds of choking  19  ，and it was a long way to the nearest   20   highway. Suddenly，at a   21   place，the car ahead pulled off the road.   22   that its owner might have engine trouble，my friend stopped and asked if anything was wrong. “  23  . ”said the other driver，“But you’ve endured my dust this far，I’ll  24  with yours the rest of the way. ”

    Another element of courtesy is empathy（善解人意），a  25   that enables a person to see into the mind or heart of someone else，to understand the pain or   26   there and to do something to minimize（使最小）it. A man  27  alone in a restaurant was trying to unscrew（旋松，旋下）the cap of a beer bottle，  28  he couldn’t do it because of badly injured  29  . He asked a young busboy to help him. The boy took the bottle，turned his back  30  and loosened the cap without difficulty. Then he  31  it again. Turning back to the man，he  32  to make great efforts to open the bottle without success.   33  he took it into the kitchen and returned shortly，saying that he had managed to loosen it，but only with a pair of pliers（钳子）.

Yet another component（组成部分）of politeness is the ability to treat all people  34  ，regardless of all status or importance.   35  when you have doubts about some people，act as if they are worthy of your best manners，you may also be astonished to find out that they really are.

Courtesy is the key to a happier world.

―     she be in the laboratory？

―She      still be there；I saw her there an hour ago.

A. Should；can                                        B. Might；may            

C. Can；might                                          D. Can；must

The manager，     it clear to us that he didn’t agree with us，left the meeting room.

A. making                                                 B. having made            

C. who has made                                       D. made