选择知识点

    Race walking shares many fitness benefits with running，research shows，while most likely contributing to fewer injuries．It does，however，have its own problem．

    Race walkers are conditioned athletes．The longest track and field event at the Summer Olympics is the 50-kilometer race walk，which is about five miles longer than the marathon．But the sportˈs rules require that a race walkerˈs knees stay straight through most of the leg swing and one foot remain in contact（接触）with the ground at all times．Itˈs this strange form that makes race walking such an attractive activity，however，says Jaclyn Norberg，an assistant professor of exercise science at Salem State University in Salem，Mass．

    Like running，race walking is physically demanding，she says．According to most calculations，race walkers moving at a pace of six miles per hour would burn about 800 calories（卡路里）per hour，which is approximately twice as many as they would burn walking，although fewer than running，which would probably burn about 1，0000 or more calories per hour．

    However，race walking does not pound the body as much as running does，Dr． Norberg says．According to her research，runners hit the ground with as much as four times their body weight per step，while race walkers，who do not leave the ground，create only about 1.4 times their body weight with each step．

    As a result，she says，some of the injuries associated with running，such as runnerˈs knee，are uncommon among race walkers．But the sportˈs strange form does place considerable stress on the ankles and hips，so people with a history of such injuries might want to be cautious in adopting the sport．In fact，anyone wishing to try race walking should probably first consult a coach or experienced racer to learn proper technique，she says．It takes some practice．

Why are race walkers conditioned athletes？
A. They must run long distances． B. They are qualified for the marathon． C. They have to follow special rules． D. They are good at swinging their legs．
What advantage dose race walking have over running？
A. Itˈs more popular at the Olympics． B. Itˈs less challenging physically． C. Itˈs more effective in body building． D. Itˈs less likely to cause knee injuries．
What is Dr． Norbergˈs suggestion for someone trying race walking？
A. Getting expertsˈ opinions． B. Having a medical checkup． C. Hiring an experienced coach． D. Doing regular exercises．
Which word best describes the authorˈs attitude to race walking？
A. Skeptical． B. Objective． C. Tolerant． D. Conservative．

Awesome Renaissance Festivals
The Renaissance（复兴）is often romanticized in books． But there's a specific type of live event that caters to（迎合）those who want to pretend they're walking through the 16th-century England．
Texas Renaissance Festival
The Texas Renaissance Festival is the largest event of its kind in the country． It takes place over nine weekends in Todd Mission． When it first started over four decades ago， the festival drew 30，000 people． Now， it sees over a half-million attendees during its run each October and November． Each weekend has a different theme to keep happenings fresh for repeat visitors．
Sterling Renaissance Festival
The Sterling Renaissance Festival， held on weekends in July and August， takes place in Warwick， which has been created to look like a 16th century English town． Actors play the role of real historical figures like Queen Elizabeth I． The performers not only play on stages， but also wander around interacting with attendees． This gives the Sterling festival more of a "living history" feel than other similar events．
Bristol Renaissance Faire
The Bristol Renaissance Faire is held in July and August． Like Sterling， this one is set during the period of Elizabeth I． An actor playing the part of the famous English ruler makes an appearance with her "court" each year． Other actors also take part in the Bristol Faire． Many of these performers are professionals from Second City and the Players Workshop．
Arizona Renaissance Festival
Renaissance festivals are often summertime affairs． But that's not the case in Arizona， where the Arizona Renaissance Festival kicks off in February and runs through the end of March． This helps the fest-goers avoid the hot Southwest summertime， and it also allows for special themed weekends． The Renaissance Festival is a big attraction here， drawing about 250，000 people per year．



Where can visitors enjoy the largest Renaissance Festival？ ______

A. In Warwick．
B. In Second City．
C. In Todd Mission．
D. In Arizona．

What makes Sterling Renaissance Festival special？ ______

A. People can see "Queen Elizabeth I"．
B. It is held on weekends in July and August．
C. It gives people more of a "living history" feel．
D. It takes place in a town built in the 16th century．

Which festival takes place in spring？ ______

A. Bristol Renaissance Faire．
B. Texas Renaissance Festival．
C. Sterling Renaissance Festival．
D. Arizona Renaissance Festival．

    For those who can stomach it，working out before breakfast may be more beneficial for health than eating first，according to a study of meal timing and physical activity．

    Athletes and scientists have long known that meal timing affects performance．However，far less has been known about how meal timing and exercise might affect general health．

    To find out，British scientists conducted a study．They first found 10 overweight and inactive but otherwise healthy young men，whose lifestyles are，for better and worse，representative of those of most of us．They tested the menˈs fitness and resting metabolic （新陈代谢的） rates and took samples （样品） of their blood and fat tissue．

    Then，on two separate morning visits to the scientistsˈ lab，each man walked for an hour at an average speed that，in theory，should allow his body to rely mainly on fat for fuel． Before one of these workouts，the men skipped breakfast， meaning that they exercised on a completely empty stomach after a long overnight fast（禁食）．On the other occasion，they ate a rich morning meal about two hours before they started walking．

    Just before and an hour after each workout，the scientists took additional samples of the menˈs blood and fat tissue．

    Then they compared the samples．There were considerable differences．Most obviously，the men displayed lower blood sugar levels at the start of their workouts when they had skipped breakfast than when they had eaten．As a result，they burned more fat during walks on an empty stomach than when they had eaten first．On the other hand，they burned slightly more calories（卡路里）， on average，during the workout after breakfast than after fasting．

    But it was the effects deep within the fat cells that may have been the most significant，the researchers found Multiple genes behaved differently，depending on whether someone had eaten or not before walking．Many of these genes produce proteins （蛋白质） that can improve blood sugar regulation and insulin（胰岛素） levels throughout the body and so are associated with improved metabolic health．These genes were much more active when the men had fasted before exercise than when they had breakfasted．

    The implication of these results is that to gain the greatest health benefits from exercise，it may be wise to skip eating first．

The underlined expression "stomach it" in Paragraph 1 most probably means "____"．
A. digest the meal easily B. manage without breakfast C. decide wisely what to eat D. eat whatever is offered
Why were the 10 people chosen for the experiment？
A. Their lifestyles were typical of ordinary people． B. Their lack of exercise led to overweight． C. They could walk at an average speed． D. They had slow metabolic rates．
What happened to those who ate breakfast before exercise？
A. They successfully lost weight． B. They consumed a bit more calories． C. They burned more fat on average． D. They displayed higher insulin levels．
What could be learned from the research？
A. A workout after breakfast improves gene performances． B. Too much workout often slows metabolic rates． C. Lifestyle is not as important as morning exercise． D. Physical exercise before breakfast is better for health．

Rainforests are home to a rich variety of medicinal plants, food, birds and animals. Can you believe that a single bush （灌木丛） in the Amazon may have more species of ants than the whole of Britain! About 480 varieties of trees may be found in just one hectare of rainforest.
  Rainforests are the lungs of the planet - storing vast quantities of carbon dioxide and producing a significant amount of the world's oxygen. Rainforests have their own perfect system for ensuring their own survival；the tall trees make a canopy（树冠层） of branches and leaves which protect themselves, smaller plants, and the forest animals from heavy rain,intense dry heat from the sun and strong winds.
  Amazingly, the trees grow in such a way that their leaves and branches, although close together, never actually touch those of another tree. Scientists think this is the plants' way to prevent the spread of any tree diseases and make life more difficult for leaf-eating insects like caterpillars. To survive in the forest, animals must climb, jump or fly across the gaps. The ground floor of the forest is not all tangled leaves and bushes, like in films, but is actually fairly clear. It is where dead leaves turn into food for the trees and other forest life.
  They are not called rainforests for nothing! Rainforests can generate 75% of their own rain. At least 80 inches of rain a year is normal - and in some areas there may be as much as 430 inches of rain annually. This is real rain - your umbrella may protect you in a shower, but it won't keep you dry if there is a full rainstorm. In just two hours, streams can rise ten to twenty feet. The humidity（湿气）of large rainforests contributes to the formation of rainclouds that may travel to other countries in need of rain.



What can we learn about rainforests from the first paragraph？ ______

A. They produce oxygen.
B. They cover a vast area.
C. They are well managed.
D. They are rich in wildlife.

Which of the following contributes most to the survival of rainforests？ ______

A. Heavy rains.
B. Big trees.
C. Small plants.
D. Forest animals.

Why do the leaves and branches of different trees avoid touching each other？ ______

A. For more sunlight.
B. For more growing space.
C. For self-protection.
D. For the detection of insects.

What can be a suitable title for the text？ ______

A. Life-Giving Rainforests
B. The Law of the Jungle
C. Animals in the Amazon
D. Weather in Rainforests