B

    Have you ever wondered why the roots of the plants always know which way to grow—into the soil but not above it? Some British scientists have recently solved this mystery.    

      It turns out that roots have special hairs that tie them into the soil and help them grow their way past obstacles, a team at the John Inners Center in Norwich reports in the February 29 issue of Journal Science.

    "The key is in the fuzzy(有绒毛的) coat of hairs on the roots of plants," says professor Liam Dolan. "We have found a growth control system that enables these hairs to find their way and to become longer when their path is clear."

    Root hairs explore the soil in much the same way a person would feel their way in the dark. If they come across an obstacle, they make their way around until they can continue growing in an opening. I the meantime, the plant is held in place as the hairs grip the soil.

    The hairs are guided by a clever chemical trick. A protein(蛋白质) at the tip of the root hairs called RHD2 helps them to take calcium(钙) from the soil. Calcium makes the hairs grow, and produce more RHD2, and take more calcium.

    But when an obstacle blocks the hair's path, or the hair reaches the surface of the soil, the cycle is broken and growth starts in another direction.

    This system gives plants the flexibility to explore a complex environment and to live in even the most unpromising soils, says Dolan.

    In poor soils such as in parts of Australia and Africa, native plants have adapted by producing enormous numbers of root hairs. A better understanding of this adaptation will allow scientists to develop hairy rooted crops that can grow in unfriendly environments.

    According to Dolan, "Research in the John Inners Center is taking a breeding approach(育种方法) to increase hair length in wheat but it will be some time before new cultivars(栽培变种) are developed."

—We hear so much about exercises these days. So even experts can't agree on which exercises are best. Now some doctors are strongly encouraging arm exercises.

—Arm exercises? {#blank#}1{#/blank#}

—{#blank#}2{#/blank#} They say that arm exercises are a way to become physically healthy.

—But don't arm exercises raise your blood pressure?

—Yes. But the articles I read supply ways to make up for that.

—How?

—By adding leg exercises, so that the arms don't do all the work.

—{#blank#}3{#/blank#}

—Sounds right to me. I quite agree with you.

—{#blank#}4{#/blank#}

—They mentioned quite a few, but some of the popular ones are cycling with special

bicycles that make you use both your arms and legs.

—{#blank#}5{#/blank#} So I'd like to have a try.

—The same with me.

A. So what exercises do the experts suggest?

B. The more leg exercises you do, the better you are.

C. And in turn I'm sure that they're also a good chance of losing weight.

D. Actually that's not the main reason.

E. What's your opinion about this?

F. Is that because our arms are too fat or soft?

G. I can hardly believe it.

UrbanizationUntil relatively recently, the vast majority of human being lived and died without ever seeing a city. The first city was probably founded no more than 5,500 years ago.{#blank#}1{#/blank#}In fact, nearly everyone lived on farms or in tiny rural (乡村的) villages. It was not until the 20th century that Great Britain became the first urban society in history—a society in which the majority of people live in cities and do not farm for a living.Britain was only the beginning.{#blank#}2{#/blank#}．The process of urbanization—the migration (迁徙) of people from the countryside to the city—was the result of modernization, which has rapidly transformed how people live and where they live.In 1900, fewer than 40% of Americans lived in urban areas. Today, over 82% of Americans live in cities. Only about 2% live on farms.{#blank#}3{#/blank#}Large cities were impossible until agriculture became industrialized. Even in advanced agricultural societies, it took about ninety­five people on farms to feed five people in cities.{#blank#}4{#/blank#}Until modern times, those living in cities were mainly the ruling elite (精英) and the servants, laborers and professionals who served them. Cities survived by taxing farmers and were limited in size by the amount of surplus（过剩）food that the rural population produced and by the ability to move this surplus from farm to city.Over the past two centuries, the Industrial Revolution has broken this balance between the city and the country.{#blank#}5{#/blank#}Today, instead of needing ninety­five farmers to feed five city people, one American farmer is able to feed more than a hundred non­farmers.

    Taking on a part-time job while pursuing a degree is hard work, but there are great benefits from that. Students with part-time jobs can eam their own money, develop good time-management skills, and gain experience in the workplace.

    {#blank#}1{#/blank#}As they come into adulthood, earning an income can increase their confidence. Some students need to work through school to afford tuition.{#blank#}2{#/blank#} Still, the money will be theirs to spend as they wish, and they may appreciate it more because they worked for it.

    Students taking on a job on top of their studies will have less free time than non-working students{#blank#}3{#/blank#} They learn to skip fun activities to finish their responsibilities. This prepares them for life after school when they can't find excuses for work that's not finished in time,

    Often, students take jobs that introduce them to their preferred career after school is over{#blank#}4{#/blank#} Even students who work in places not connected to their majors will look more impressive to potential employers. Employers look for employees who understand the work environment and work well as part of a team{#blank#}5{#/blank#}That will make it much easier for them to change their roles after leaving school.

A. Others will set the money aside to pay back student loans.

B. Other students may have to get help from their parents.

C. Students having part-time jobs usually get employed easily after graduation.

D. Having a part-time job helps students to get accustomed to the professional world.

E. They tend to be better planners as they make sure they complete every task on deadline.

F. Students who take part-time jobs will have more money than they would have otherwise.

G. This allows them to gain experience in the business and begin meeting people in that field.

    Everyone knows that fish is good for health. {#blank#}1{#/blank#} But it seems that many people don't cook fish at home. Americans eat only about fifteen pounds of fish per person per year, but we eat twice as much fish in restaurants as at home. Buying, storing, and cooking fish isn't difficult{#blank#}2{#/blank#} This text is about how to buy and cook fish in an easy way.

    {#blank#}3{#/blank#} Fresh fish should smell sweet: you should feel that you're standing at the ocean's edge. Any fishy or strong smell means the fish isn't fresh.{#blank#}4{#/blank#} When you have bought a fish and arrive home, you'd better store the fish in the refrigerator if you don't cook it immediately, but fresh fish should be stored in your fridge for only a day or two. Frozen fish isn't as tasty as the fresh one.

    There are many common methods used to cook fish. {#blank#}5{#/blank#} First, lean it and season it with your choice of spices(调料). Put the whole fish on a plate and steam it in a steam pot for 8 to 10 minutes if it weighs about one pound. (A larger one will take more time.) Then, it's ready to serve.

A. Do not buy it.

B. The easiest is to steam it.

C. This is how you can do it.

D. It just requires a little knowledge.

E. The fish will go bad within hours.

F. When buying fish, you should first smell it.

G. The fats in fish are thought to help prevent heart disease.

    Singapore's public transport system is one of the best in the world, so you should have no problem finding your way around like a local. There are three main forms of public transport that you would find in any other major city－trains, buses and taxis.

    TRAINS

    Trains run from 6:00 am to midnight. Single trip tickets start at 80 cents. If you buy an EZ-Link card for $15, you can ride the trains and buses as you like. If you need more information, just call Transit Link on 1800 767 4333.

    BUSES

    There are several bus services in Singapore and fares start at 80 cents. Be sure to always ask the driver the cost of your ticket as he cannot give change. If you need help, just call Transit Link on 1800 767 4333.

    TAXIS

    There are three main taxi companies－City Cab (6552 2222), Comfort (6552 1111) and Tibs (6552 8888). Booking can also be easy by calling the numbers listed above.

    RENTAL CARS

    Driving in Singapore is a pleasure and if you like to travel at your own pace, renting a car is a good choice. Renting takes away the hassle of getting to places around Singapore. Just sit back and enjoy the city. It also means you'll get to see a lot more that a train or a bus won't let you see.

    For car rental, call Avis on +65 6737 1668.