What does fizz (气泡) taste like? In Bubbly (多泡的)drinks such as sodas, tiny bubbles give the drink a lift--- and have a distinct taste, In a new study on mice, scientists have connected that fizzy-taste feeling to the ability to taste sourness, such as that of oranges or vinegar.

Scientists first thought the taste of bubbles came from the bubbles bursting on the tongue, but now ate starting to think differently. Charles Zuker, of Columbia University, and his team studied the nervous system of mice to understand how the tongue tastes carbon dioxide, which is the gas that makes up the bubbles.

       Animals, including human beings, are able to detect different tastes by using taste buds(味蕾) which pick up tastes in the mouth, and then send them to the brain. In the experiment, different groups of mice were genetically engineered to be missing one of the senses involved in taste. “Genetically engineered” means the researchers were able to turn off the switches for certain senses by changing the genes responsible for taste. The mice in one group could not taste sweet; another, sour; the third, bitter, and the fourth, salt. When the scientists gave carbon dioxide to the mice, the nervous systems of all the mice responded to the gas, except those of the mice that could not taste sour.

       This shows that the taste of the bubbles must be sour, and that by turning off the ability of the mice to taste sour, the scientists also turned off their ability to taste carbon dioxide. When they studied the cells that detect sourness, the researchers found a protein attached to the cells that is important to the process of tasting carbon dioxide. When carbon dioxide comes into contact with this protein, the protein knocks off particles called protons. These protons(质子), in turn, travel to the brain, which says ,” Hey! That’s a taste!”

       It may seem like a lot of work to get from a can of soda to a taste, but the science of the senses is anything but simple, “  Taste is a challenging system to study,” one researcher says.

1. What is the most important function of the bubbles?

A. To look interesting .                   B. To make drinks taste good.

C. To make drinks funny.                D. To produce a lot of fizz.

2.From the experiment the researchers learned that______.

A. sourness has nothing to do with the taste of bubbles.

B. there is a connection between sourness and bubbles.

C. the taste of bubbles is better if it’s less sour.

D. most mice cannot taste carbon dioxide.

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

A. the taste of bubbles is produced by the bubbles bursting on the tongue.

B. the nervous systems of mice show how the tongue tastes carbon dioxide.

C. taste seems simple but is very complex to research.

D. nerve cells sending signals to the brain is the first step in tasting something.

4. Which of the following would be the best title for the passage?

A. Nervous Systems Understand How the Tongue Tastes.                    

B. The Process of Taste

C. The taste of Bubbles.                                              

D. Different Animals Detect Different Tastes.

The story happened on a hot heavy rainy day.

    After class, I took a few bottles to go and   36   some water from the water room. Oh! There were so many people! I had to wait   37   the rain. My hair didn't get wet because I wore a hat, but my clothes  38  .

    When at last it was my   39   , I filled the bottles as quickly as possible. I began making my way back when I saw a boy   40   towards me. He   41   two umbrellas in his hand. He shouted hello and as he came   42   , I recognized that it was Tom.

    He   43   my classmate for nearly three years, but we never   44   more than ten sentences. He was silent, but I liked talking. We were quite   45   people and had nothing in common. I didn't   46   him and even didn't want to see him.

    "Hey! What's wrong?" His words   47   me out of my thought. "I saw you   48   in the rain, so I brought you this umbrella. But it seems a little   49   , your clothes are already wet,"

    On hearing this, I was so   50   that I couldn't say a single word.

"Don't just stand there. Let's go!" He said and held the umbrella for me. We walked towards   51   and this time we talked   52   .

    "I know you don't like me, but I want to   53   with you." he said, "You may think I am silent, but it is because I can't find the right   54   to say."

The rain finally stopped and we saw a rainbow in the blue sky. I said to myself, "It is wrong to  55  someone only by his appearance.

1.A. collect                             B. drink      C.move              D. hold

2.A. under                                    B. in                    C.at                              D. on

3.A. did                                B. got                  C.is                              D. does

4.A. wish                              B. duty      C.job                           D. turn

5.A. come                                     B. came     C.coming                    D. comes

6.A. had held                      B. has held  C.was holding         D. holds

7.A. near                                       B. nearly  C.nearer                     D. nearest

8.A. has been                B. had been  C.is                           D. would be

9.A. shared                             B. talked     C.spoke             D. called

10.A. the same                            B. familiar  C.strange                 D. the best

11.A. hate                                     B. ignore  C.like                 D. forget

12.A. brought                     B. made    C.got                           D. surprised

13.A. stood                                    B. stand     C.standing         D. are standing

14.A. early                                    B. frequent  C.usual                    D. late

15.A. moving                      B. move    C.moved                     D. moves

16.A. the meeting room   B. the park  C.the playground D. the dormitory

17.A. nothing                      B. too much  C.a lot                     D. something

18.A. make friends       B. have wordsC.have a speech  D. shake a hand

19.A. times                                   B. words  C.places                      D. news

20.A. understand               B. see                 C.judge              D. decide

第三部分：阅读理解(共15小题；每小题2分，满分30分)
阅读下列短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。
A handsome middle­aged man walked quietly into the cafe and sat down. Before he ordered，he couldn’t help but notice a group of younger men at the table next to him. It was obvious they were making fun of something about him and it wasn’t until he remembered he was wearing a small pink ribbon(丝带) on the lapel of his suit that he became aware of what the joke was all about.
The man pretended not to notice it，but the whisper and laughter began to get to him. He looked one of the rude young men straight into the eye，placed his hand beneath the ribbon and asked，“This？”
With that the young men all began to laugh out loud. The man he spoke to said，“Hey，sorry，man, but we were just commenting on how pretty your little pink ribbon looks against your blue jacket！”
The middle­aged man calmly invited the joker to come over to his table, and politely seated him. As uncomfortable as he was, the young guy had to, not really sure why. In a soft voice，the middle­aged man said, “I wear this ribbon to bring awareness about breast cancer. I wear it in my mother’s honor.”
“Oh, sorry. She died of breast cancer？”
“No, she didn’t. She’s alive and well. But her breasts nourished me as a baby，and were a soft resting place for my head when I was scared or lonely as a little boy. I’m very grateful for my mother’s breasts, and her health.”
“Umm,” the young replied “yeah.”
“And I wear this ribbon to honor my wife” the man continued.
“And she’s okay, too？”the young guy asked.
“Oh, yes. She’s fine. Her breasts have been a great source of loving pleasure for both of us，and with them she nurtured and nourished our daughter 23 years ago. I’m grateful for my wife’s breasts，and her health.”
“Uh, huh. And I guess you wear it to honor your daughter, also？”
“No. It’s too late to honor my daughter by wearing it now...”
Shaken and ashamed，the young guy said, “Oh, I’m so sorry，mister.”
“So, in my daughter’s memory, too, I proudly wear this little ribbon, which allows me the opportunity to enlighten others. And here...”With this，he reached in his pocket and handed the young man a little pink ribbon. The young guy looked at it, slowly raised his head and asked, “...？”
51．The young men joked about the middle­aged man’s________.
A．looks       B．ribbon      C．attitude     D．clothes
52．What may have happened to the man’s daughter?
A．She died of breast cancer.                B．She was ill with cancer.
C．She had gone abroad.                    D．She got married.
53．What will the young man probably ask at the end of the story?
A．May I give it to my mother?           B．Can you help me put it on?
C．Will you please forgive me?            D．Shall we have some drink together?
54．What is the best title for the passage?
A．An Unusual Meeting               B. An Impressive Lesson
C．Be Grateful to Your Beloved     D. A little Pink Ribbon

Learning experiences happen to us throughout our lives. Not long ago, I had one that I would like to __16__.
I was going to Marblehead with my sailboat team. The team was racing down the highway at 85 mph __17_ we realized we were __18_. Luckily, we saw a rest area ahead. I had a brand-new $20 bill. I was so __19_ because I had never had that kind of cash before. But spending it on __20__ seemed like throwing it away. We all rushed into the pizza line. __21__ I got a pizza and a drink, and walked to my table. About halfway through the meal, I __22_ I had not actually handed any money to the cashier. I had just __23__ out, and nobody had noticed. I felt terrible.
My conscience (良心) opened its mouth and swallowed me in one big bite. I couldn’t __24__ over it. I just couldn’t go back to the cashier and __25__ for my stolen pizza. I was so upset that I __26__ to give myself the pleasure of an ice cream for __27__ that someone would say, “Hey, Jeff, why not you use the change __28__ the pizza instead of that nice, new $20 bill?” I was not so __29__ of my cash now. For the next two years, whenever I was __30__ of the “pizza incident”, I would say to myself, “Don’t think about it…”
I have learned two things from this __31__. Maybe I was a fool for __32__ in to my conscience, and being too stupid to appreciate a __33__ pizza. But the real lesson is that even if you get away with what you have done, your conscience will __34__ up with you.
This reflects the saying, “Coward (懦夫) dies a thousand deaths, a hero dies one.” I was a coward and have felt terrible about that incident at least a thousand times. If I had been a “__35__” and gone back to pay for the pizza, I would have felt a little uncomfortable about it only one, or maybe twice.