Unlike other cell membranes, the nuclear envelope has no pores.

A、all chromosomes found in a normal human cell

B、those chromosomes found in egg or sperm cells

C、all chromosomes other than the sex chromosomes

D、chromosome pairs with unlike members

A．1.？Cancer cells have a reduced dependence on signals from other cells for their survival, growth, and division. 2.？Cancer cells can survive levels of stress and internal derangement that would cause normal cells to kill themselves by apoptosis.

B．3.？Unlike most normal human cells, cancer cells can often proliferate indefinitely.？4. Most cancer cells are genetically unstable,with a greatly increased mutation rate and an abnormal number of chromosomes.

C．5. Cancer cells are abnormally invasive,at least partly because they often lack certain cell adhesion molecules, such as cadherins, that help hold normal cells in their proper plac

E．？6. Cancer cells are abnormally avid for nutrients, which they use to generate much of their ATP by glycolysis in the cell cytosol.

D．7. Cancer cells can survive and proliferate in abnormal locations, whereas most normal cells die when misplace

D．？8. As cancer cells evolve,they secrete signals that influence the behavior of cells in the surrounding connective tissue,thereby modifying the tumor’s microenvironment.

The term "virus" is derived from the Latin word for

position, or slime. It was originally applied to the noxious

stench emanating from swamps that was thought to cause a

variety of disease in the centuries before microbes were S1.______

discovered and specifically linked to illness. But it was S2.______

until almost the end of the nineteenth century that a true

virus was proven to be the reason of a disease. S3.______

The nature of viruses made them impossible to detect

for many years, even after bacteria had been discovered and

studied. Not only are viruses too small to be seen with a

light microscope, they also cannot be detected through their S4.______

biological activity, except as it occurs in conjunction with

other organisms. In fact, viruses show no traces of biological

activity by themselves. Unlike bacteria, they are not living

agents in the strictest way. Viruses are very simple pieces S5.______

of organic material composing only of nucleic acid, either S6.______

DNA or RNA, enclosed with a coat of protein made up of S7.______

simple structural units. (Some viruses also contain

carbohydrates and lipid.) They are parasites require S8.______

human, animal, or plant cells to live. The virus replicates

by attaching to a cell and inject its nucleic acid; once S9.______

inside the cell, the DNA or RNA that contains the virus'

genetic information takes on the cell's biological machinery, S10.______

and the cell begins to manufacture virtual proteins rather

than its own.

【S1】

All of the cells in a particular plant start out with the

same complement of genes. How then can these cells

differentiate and form. structures as different as roots,

stems, leaves, and fruits？ The answer is that only a

(5) small subset of the genes in a particular kind of cell are

expressed, or turned on, at a given time. This is accom-

plished by a complex system of chemical messengers

that in plants include hormones and other regulatory

molecules. Five major hormones have been identified:

(10) auxin, abscisic acid, cytokinin, ethylene, and gibberel-

lin. Studies of plants have now identified a new class of

regulatory molecules called oligosaccharins.

Unlike the oligosaccharins, the five well-known plant

hormones are pleiotropic rather than specific, that is,

(15) each has more than one effect on the growth and devel-

opment of plants. The five has so many simultaneous

effects that they are not very useful in artificially

controlling the growth of crops. Auxin, for instance,

stimulates the rate of cell elongation, causes shoots to

(20) grow up and roots to grow down, and inhibits the

growth of lateral shoots. Auxin also causes the plant to

develop a vascular system, to form. lateral roots, and to

produce ethylene.

The pleiotropy of the five well-studied plant

(25) hormones is somewhat analogous to that of certain

hormones in animal. For example, hormones from the

hypothalamus in the brain stimulate the anterior lobe

of the pituitary gland to synthesize and release many

different hormones, one of which stimulates the release

(30) of hormones from the adrenal cortex. These hormones

have specific effects on target organs all over the body.

One hormone stimulates the thyroid gland, for

example, another the ovarian follicle cells, and so forth.

In other words, there is a hierarchy of hormones.

(35) Such a hierarchy may also exist in plants. Oligosac-

charins are fragments of the cell wall released by

enzymes: different enzymes release different oligosac-

charins. There are indications that pleiotropic plant

hormones may actually function by activating the

(40) enzymes that release these other, more specific chemical

messengers from the cell wall.

According to the passage, the five well-known plant hormones are not useful in controlling the growth of crops because______

A．it is not known exactly what functions the hormones perform

B．each hormone has various effects on plants

C．none of the hormones can function without the others

D．each hormone has different effects on different kinds of plants

E．each hormone works on only a small subset of a cell’s genes at any particular time

Part A

Directions: Read the following four texts. Answer the questions below each text by choosing A, B, C or D . Mark your answers on ANSWER SHEET 1.

The term "virus" is derived from the Latin word for poison, or slime. It was originally applied to the noxious stench emanating from swamps that was thought to cause a variety of diseases in the centuries before microbes were discovered and specifically linked to illness. But it was not until almost the end of the nineteenth century that a true virus was proven to be the cause of a disease.

The nature of viruses made them impossible to detect for many years, even after bacteria had been discovered and studied. Not only are viruses too small to be seen with a light microscope, they also cannot be detected through their biological activity, except as it occurs in conjunction with other organisms. In fact, viruses show no traces of biological activity by themselves. Unlike bacteria, they are not living agents in the strictest sense. Viruses are very simple pieces of organic material composed only nucleic acid, either DNA or RNA, enclosed in a coat of, protein made up of simple structural units. They are parasites, requiring human, animal or plant cells to live. The virus replicates by attaching to a cell and injecting its nucleic acid; once inside the cell, the DNA or RNA that contains the virus' genetic information takes over the cell's biological machinery, and the cell begins to manufacture viral protein rather than its own.

Which of the following is the best title for the passage？

A．New Developments in Viral Research.

B．Exploring the Causes of Disease.

C．DNA: Nature's Building Block.

D．Understanding Viruses.

听力原文： Good morning. Let me go ahead with our presentation on the company's sales records for the past year. As you see here from this chart, last year's sales figures have been fairly high, except for August, September, and October. This indicates that there is a great need for us to come up with a new fall product line that satisfies consumers to offset the loss we encountered last year. Our view is that, unlike other seasons, fall lacks any unique characteristics in terms of our clothing line.

We are currently receiving ideas from every department on new items for this fall, but regrettably, none of them have proved to be satisfactory. However, we still recommend that people contribute any views to us, and anyone whose idea is chosen will be rewarded with a bonus. We sense that other companies are experiencing the same kind of problem we have, and I personally think we have to take advantage of this opportunity to dominate the market.

How will the company overcome the decline in sales？

A．Develop new items to sell.

B．Advertise the items more aggressively.

C．Downsize the company.

D．Use ideas from consumers.

nlike batteries, fuel cells don’t run down or need recharging. As long as there is a constant source of fuel and oxygen, fuel cells will continue to generate power. And they don’t burn the fuel – the electricity is produced directly.

one another.

I was walking in the park with a friend recently, and his cell phone rang, interrupting our conversation. There we were, walking and talking on a beautiful sunny day and -- poof! -- I became invisible, absent from the conversation.

The park was filled with people talking on their cell phones. They were passing other people without looking at them, saying hello, noticing their babies or stopping to pet their puppies. Evidently, the untethered electronic voice is preferable to human contact.

The telephone used to connect you to the absent. Now it makes people sitting next to you feel absent. Recently I was in a car with three friends. The driver shushed the rest of us because he could not hear the person on the other end of his cell phone. There we were, four friends zooming down the highway, unable to talk to one another because of a gadget designed to make communication easier.

Why is it that the more connected we get, the more disconnected I feel？ Every advance in communications technology is a setback to the intimacy of human interaction. With e-mail and instant messaging over the Internet, we can now communicate without seeing or talking to one another. With voice mail, you can conduct entire conversations without ever reaching anyone. If my mom has a question, I just leave the answer on her machine.

As almost every conceivable contact between human beings gets automated, the alienation index goes up. You can't even call a person to get the phone number of another person anymore. Directory assistance is almost always fully automated.

Pumping gas at the station？ Why say good-morning to the attendant when you can swipe your credit card at the pump and save yourself the both.

Making a deposit at the bank？ Why talk to a clerk who might live in the neighborhood when you can just insert your card into the ATM？

Pretty soon you won't have the burden of making eye contact at the grocery store. Some supermarket chains are using a self-scanner so you can check yourself out, avoiding those annoying clerks who look at you and ask how you are doing.

I am no Luddite. I own a cell phone, an ATM card, a voice-mall system, an e-mail account. Giving them up isn't an option -- they're great for what they're intended to do. It's their unintended consequences that make me cringe.

More and more, I find myself hiding behind e-mall to do a job meant for conversation. Or being relieved that voice mail picked up because I didn't really have time to talk. The industry devoted to helping me keep in touch is making me lonelier -- or at least facilitating my antisocial instincts.

So I've put myself on technology restriction: no instant messaging with people who live near me, no cell-phoning in the presence of friends, no letting the voice mall pick up when I'm home.

What good is all this gee-whiz technology if there's no one in the room to hear you exclaim, "Gee whiz？"

Saying "the unuttered electronic voice is preferable to human contact", the author is ______.

A．telling the truth

B．expressing his opinion

C．being sarcastic

D．describing a problem

听力原文：M: What did you do to celebrate your birthday？

W: My friends took me to see Cirque du Soleil. What a show! It was unlike anything I had ever seen before. The performances were mesmerizing---they were art!

M: Wow, it sounds like you really enjoyed yourself. What distinguishes Cirque du Soleil from other circuses？

W: It simply has class. The acts have a certain style. that you don't see in other circuses. There is soft, romantic lighting and fantastic music which ranges from classical to jazz. But, what really sets the circus apart is the costumes with their beautiful fabrics, rich colors and fairy tale designs.

M: It sounds amazing, but I always feel a little guilty when I go to the circus. It seems so cruel to use animals for our entertainment.

W: Cirque du Soleil doesn't believe in using animals. They rely on human performers including acrobats, trapeze artists and contortionists.

M: That's wonderful. I wish other circuses would do the same.

W: And the human performances are much more fun. There was one clown who actually juggled eight wine glasses at one time. I couldn't believe it. There was also a magician who performed a series of comical tricks involving members of the audience. I loved the whole thing. You really should see them while they are in town.

M: I think I'll go this weekend.

(23)

A．It's a concert.

B．It's a circus.

C．It's a game.

D．It's a movie.

Reading Comprehension: I Americans generally consider themselves to be frank, open, and direct in their dealings with other people. In their daily conversation, they may chat with each other in a more direct way. “Let’s lay our cards on the table,” they say. Or, “Let’s stop playing games and get to the point.” Unlike statements from other nations, these and many other phrases show the Americans’ idea that people should clearly state what they think about and what they want. Americans tend to believe that disagreements are best settled by means of long discussions among the people involved. If I dislike something you are doing, I should tell you about it directly so you will know, clearly and from me personally, how I feel about it. They do not prefer to hide their feelings, which may make themselves uneasy. For them, bringing in other people to solve the problem is regarded as somewhat strange. And the former will be looked upon as one who is not brave enough to speak directly to someone else. Americans will often speak openly and directly to others about things they dislike. They will try to do so in a manner they call “constructive”, that is, a manner which the other person will not find offensive or unacceptable. If they do not speak openly about what is in their minds, they will often express their meanings in nonverbal ways (without words, but through facial expressions, body positions, and gestures). They believe it is also a good way to show their feelings. Americans are not taught, as people in many Asian countries are, that they should hide their feelings. Their words, the tone of their voices, or their facial expressions will usually reveal when they are feeling angry, unhappy, confused, or happy and satisfied. 1. According to the passage, ______________.

A、Americans don’t state clearly what they think and want

B、Americans use body language to defend other people

C、Americans seldom speak openly

D、Americans state clearly what they want