These two chemicals （interact) with each other at a certain temperature to produce a

From the letter, we can know______.

A．the two sides cooperated before

B．the Irish should pay for the transportation fee in terms of the new price

C．they use the best chemicals to improve the quality

D．they have enough storage that can supply at any time

From the letter, we can know ________.

A．the two sides cooperated before

B．the Irish should pay for the transportation fee in terms of the new price

C．they use the best chemicals to improve the quality

D．they have enough storage that can supply at any time

Zhongxing Chemicals Corporation in China exported two tons of disinfectant (消毒剂) in one container to the United States. The trade was effected on the term of CIF New York US$ 20000. Upon the reception of the consignment at New York Port, the Consignee found the disinfectant was wet and useless according to the normal function of the substance. The consignee brought the claim against the Carrier and Insurer and gave the notice to the local survey agent mentioned in the Policy without any delay. The cause and origin of the damage, in accordance with the survey report, is the moisture in the Container, resulting either from: Stuffing of the goods in an atmosphere with a high hygrometry (湿度) Accidental wetting by rainwater during the course of stuffing Stowing the bags on wet wooden bases.Questions:(可用中文回答)(1)What shall we do according to the survey report？(2) If the shipper presented a loading inspection report as follows, what measures shall we take？

听力原文： Scientists have discovered that plants themselves produce many poisonous chemicals for defense against insects. But insects have developed ways of dealing with them and, in fact, have been eating plants for about 250 million years. Now insects are using these same mechanisms to deal with man-made poisons—insecticides. This is why resistance of insects to insecticides has developed so rapidly.

What should be done？ Scientists studying the problem suggest that farmers use less insecticides. At the moment, farmers regularly spray crops as a precaution against problems that are caused by large numbers of pests. They should, instead, spray only where pests have actually been seen. Secondly, farmers could use a combination of two or three insecticides at once. To survive, the insects would need to become resistant to two or more insecticides at the same time.

The most surprising suggestion, perhaps, is that at certain times of the year, farmers should actually try to attract insects onto the crops they are trying to protect. The new insects will mate with those which survived from a certain kind of insecticide and will lessen the latter's resistance to it.

Scientist hope that these and other measures will postpone the day when farmers and scientists will have to stand by while new super-bugs which may be resistant to all poisons invade our farms and devour our crops.

What have scientists discovered about plants and insects？

A．Plants produce many poisonous chemicals for defense against insects.

B．Insects develop ways of dealing with natural poisonous chemicals but not man-made ones.

C．Farmers must spray plants all the time.

D．Farmers must use different brands of insecticides.

听力原文： Scientists have observed that plants themselves produce many poisonous chemicals for defense against insects. But insects have developed ways of dealing with them and,in fact,have been eating plants for about 250 million years.Now insects are using these same mechanisms to deal with man-made poisons-insecticide.This is why resistance of insects to insecticide has developed so rapidly.What should be done？Scientists studyilg the problem suggest that farmers use less insecticide.At the moment,famlers regularly spray crops as a precaution against problems that are caused by large numbers of pests.They should,instead,spray only where pests have actually been seen.Secondly,farmers could use a combination of two or three jnsecticide at once.To survive,the insects would need to become resistant to two or more poisons at the same time.The most surprising suggestion,perhaps,perhaps,is that,at certain times of the year,famers should actually try to attract new insects onto the crops they are trying to protect.The new insects will mate with those which survived from a certain kind of insecticide and will lessen the latter's resistance to it.

Scientists hope that these and other measures will postpone the day when farmers and scientists will have to stand by while new super bugs which may be resistant to all our poisons invade our farms and devour our crops.

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A．There are 250 million plants eaten by insects.

B．There are fewer plants than 250 million years ago.

C．They have their way of guarding against insects.

D．They have a better immune system than before.

Questions are based on the following passage.

Cocoa contains chemicals calledflavanols （黄烷醇 ） that may help reduce the risk of strokes and heart attacks by lowering blood pressure and improving the body"s use of insulin （胰岛素 ） .

Washington chocolate producer Steve Kumar said that is one reason dark chocolate is increasingly popular among his customers. "A lot of people are attracted by dark chocolate because they just decide they love it， and they also have been reading all about the health benefits of dark chocolate，" said Kumar.

But those benefits have not been confirmed by studies involving large numbers of people. Also， during the production of chocolate， a lot of flavanols are destroyed， while sugar and fats are added to contribute to flavor.

Scientists now want to learn the benefits of flavanols in their pure form.

They plan a four-year study of 18，000 adults， who will take pills of pure cocoa flavanols， in what is being called the largest test of its kind. Jo-Ann Manson， of the Brigham and Women"s Hospital in Boston， is the lead researcher. "This pill of cocoa flavanols will avoid having the calories and the sugar and the fat found in chocolate，" said Manson. The pills also won"t have any taste. Participants，divided in two groups， will take two identical pills a day. One group"s pills will contain flavanols， while the others will getplacebo （安慰剂 ） pills. "The amount of chocolate that it would take in order to have this amount of cocoa flavanols would be more than ten times the amount that people would ordinarily eat，" said Manson.

Whatever the outcome of the study， Kumar said he"s not worried about his business. "People like the experience of actually biting into a piece of chocolate，whatever their favorites are，" he said.

The flavanol benefits test is still in the early stage， so scientists are not sure when the participants will be handed their first chocolate pills.

What chemical in cocoa may do good to the heart according to the passage？ 查看材料

A.Fat.

B.Insulin.

C.Sugar.

D.Flavanols.

uction to Seience, didn't you？

M: I sure did. Why did you ask me about that？

W: Well, I'm thinking about taking it next year. I want to know something about it beforehand.

M: As far as I'm concerned, I suggest that you not take it.

W: Why not？ Is the professor awful or is the lecturing boring？

M: The professor is nice enough. But the course is nothing but physics and chemistry with lots of equations. You can't just mix the right chemicals and watch what happens. As you go along you have to keep care notes and turn it all into a bunch of numbers and formulas after the experiment is over. It was the worst course I've ever taken.

W: What you say is no problem for me. To tell you the truth, [ like formulas and numbers. That's what I'm different from you.

M: Is it？ Then you'll love it if it is the case. But all that I was interested in was biology and we didn't get to that till the last three weeks of the class. What a year!

Who are the two speakers in the conversation？

A．A student and a professor,

B．A physicist and a biologist.

C．Two students.

D．Two professors.

ls for defense against insects. But insects have developed ways of dealing with them and, in fact, have been eating plants for about 250 million years. Now insects are using these same mechanisms to deal with man - made poisons—insecticides. This is why resistance of insects to insecticides has developed so rapidly. What should be done？ Scientists studying the problem suggest that farmers use less insecticides. At the moment, farmers regularly spray crops as a precaution against problems that are caused by large numbers of pests. They should, instead, spray only where pests have actually been seen. Secondly, farmers could use a combination of two or three insecticides at once. To survive, the insects would need to become resistant to two or more insecticides at the same time. The most surprising suggestion, perhaps, is that at certain times of the year, farmers should actually try to attract insects onto the crops they are trying to protect. The new insects will mate with those which survived from a certain kind of insecticide and will lessen the latter' s resistance to it. Scientists hope that these and other measures will postpone the saying when farmers and scientists will have to stand by while new super - bugs which may be resistant to all poisons invade our farms and devour our crops.

What conclusion can be drawn from the scientists' observation？

A．Insects have developed some sort of resistance to man - made poisons.

B．Insects have been eating plants for about 250 million years.

C．Farmers sometimes use a combination of two or three insecticides at once.

D．New insects mate with insects which survived from a certain kind of insecticide.

as a ready-made model with which to compare them. The computer model is not perfect, however. For a start, the largest mainframe. (主计算机)in the world can not compete with the potential brain power of human beings. Packed into even the thickest of human skulls are some 1,000 billion cells, or neurons, and each one can connect with thousands of its neighbors. Each connection represents a 'bit' of information and, in theory, we can carry more bits than there are atoms in the known universe.

There are two quite distinct types of memory-short-term and long-term. Our short-term memories are those which we hold on to for just as long as we need them. The vast majority of our everyday thoughts, sights and impressions are registered in the short-term memory only. They take the form. of patterns, or linked pathways, created by circulating currents of electrical energy. So long as the current is buzzing around its little route, the memory that it represents stays in the mind. But once the current dies down, the memory, too, starts to fade. While short-term memories consist of active electrical circuits, long-term memories are quite literally etched (铭刻) into our brains. It seems that if the pathways taken by a particular electrical current are well-trodden, or if the current passing along them is strong enough, the cells along the way change, so that the route or pattern is permanently marked.

Events which have strong meaning for us are particularly likely to be upgraded into the long-term memory. Part of the reason is probably that we go over and over these memories, keeping the pathways stimulated and the electrical current high. It's also likely that certain chemicals come into play, too. When we are excited, very happy, or frightened, our glands pump out chemicals such as adrenaline. One theory has it that some of these chemicals stimulate the neurons to alter their structure and forge permanent connections with each other.

It follows, then, that a memory formed when we are 'up' is more likely to stick than one registered when we are down. Several experiments seem to bear this out. In one, a group of students was first shown an exciting film, then given a list of words to memorize. Another group was shown a miserable film, then given the same learning task. Next day the group who watched the happy film could remember 20% more words than the other group.

About the memory in comparison with the computer the writer says that ______.

A．neither of them is completely reliable all the time

B．the memory is more complicated than the computer

C．the computer operates in a more organized way than the memory

D．neither of them is used to its fullest capacity all the time

听力原文： Health food is a general term applied to all kinds of food that are considered more healthful than the types of foods widely sold in supermarkets. For instance, whole grains, fried beaus, and corn oil are health foods. A narrower classification of health food is natural food, which is used to distinguish between types of the same food. Raw honey is a natural sweetener, whereas relined sugar is not. Fresh fruit is a natural food, but canned fruit, with sugars and other additives, is not. The most precise term of all and the narrowest classification within health food is organic food, which is used to describe food that has been grown on a particular kind of farm. Fruits and vegetables that are grown in gardens that are only treated with organic fertilizers, that are not sprayed with poisonous insecticides, and that are not refined after harvest, are organic foods. Meats, fish, dairy and poultry products from animals that are fed only organically-grown feed and that are not injected with hormones are organic foods.

In choosing the type of food you eat, then, you have basically two choices: inorganic, processed foods, or organic, unprocessed foods. A wise decision should include investigation of the claims that processed foods contain chemicals, some of which ate proven to be poisonous, and that vitamin content is greatly reduced in processed foods.

(30)

A．Refined food.

B．Processed food.

C．Natural food.

D．Organic food.

Fireworks

If you have ever been to an aerial fireworks show at an amusement park, baseball game, Fourth of July celebration or on New Year's Eve, then you know that fireworks have a special and beautiful magic all their own--a good show is absolutely amazing!

Have you ever wondered how this magic works？ What is launched into the sky to make these beautiful displays？ In this article, you will learn all about aerial fireworks.

Basic Components

Just about everyone in the United States has some personal experience with fireworks, either from Fourth of July or New Year's Eve celebrations. For example, you have probably seen both sparklers and firecrackers. It turns out that if you understand these two pyrotechnic (有关烟火制造术的) devices, then you are well on your way to understanding aerial fireworks! The sparkler demonstrates how to get bright, sparkling light from a firework, and the firecracker shows how to create an explosion.

Firecrackers have been around for hundreds of years. They consist of either black powder (also known as gunpowder) or flash powder in a tight paper tube with a fuse to light the powder. Black powder, discussed briefly in How Rocket Engines Work, contains charcoal, sulfur and potassium nitrate. A composition used in a firecracker might have aluminum instead of or in addition to charcoal in order to brighten the explosion.

Sparklers are very different from firecrackers. A sparkler burns over a long period of time (up to a minute) and produces extremely bright and showery light. Sparklers are often referred to as "snowball sparklers" because of the ball of sparks that surrounds the burning portion of the sparkler. If you look at Patent #3,862,865: Sparkler composition, you can see that a sparkler consists of several different compounds:

A fuel

An oxidizer

Iron or steel powder

A binder

The fuel is charcoal and sulfur, as in black powder. The binder can be sugar or starch. Mixed with water, these chemicals form. a slurry that can be coated on a wire (by dipping) or poured into a tube. Once it dries, you have a sparkler. When you light it, the sparkler bums from one end to the other (like a cigarette). The fuel and oxidizer are proportioned, along with the other chemicals, so that the sparkler burns slowly rather than exploding like a firecracker.

It is very common for fireworks to contain aluminum, iron, steel, zinc or magnesium dust in order to create bright, shimmering sparks. The metal flakes heat up until they are incandescent and shine brightly or, at a high enough temperature, actually burn. A variety of chemicals can be added to create colors. See lights and colors for a good explanation of the chemistry and physics of color in fireworks.

Aerial Fireworks

An aerial firework is normally formed as a shell that consists of four parts:

Container----usually pasted paper and string formed into a cylinder

Stars--spheres, cubes or cylinders of a sparkler-like composition

Bursting charge--firecracker-like charge at the center of the shell

Fuse—provides a time delay so the shell explodes at the right altitude

The shell is launched from a mortar. The mortar might be a short, steel pipe with a lifting charge of black powder that explodes in the pipe to launch the shell. When the lifting charge fires to launch the shell, it lights the shell's fuse. The shell's fuse bums while the shell rises to its correct altitude, and then ignites the bursting charge so it explodes.

Simple shells consist of a paper tube filled with stars and black powder. Stars come in all shapes and sizes, but you can imagine a simple star as something like sparkler compound formed into a ball the size of a pea or a dime. The stars are poured into the tube and then surrounded by b

A．Y

B．N

C．NG